diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5e2e9fd13..034ba3db4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,11 +1,16 @@
 # v1.6.0-rc.5
 ## mm/dd/2019
 
+1. [](#new)
+    * Added `FlexObjectInterface::getDefaultValue()` and `FormInterface::getDefaultValue()`
 1. [](#improved)
     * Added `Content-Type: application/json` body support for PSR-7 `ServerRequest`
     * Remove PHP time limit in `ZipArchive`
+    * DebugBar: Resolve twig templates in deprecated backtraces in order to help locating Twig issues 
 1. [](#bugfix)
     * Fixed `Undefined method closure::fields()` when getting avatar for user, thanks @Romarain [#2422](https://github.com/getgrav/grav/issues/2422)
+    * Grav 1.6: Added `Flex[Class]::getFlexType()` to all flex classes to have the interface for all Flex classes
+    * FlexObjects: Remove null values during save
 
 # v1.6.0-rc.4
 ## 03/20/2019
diff --git a/system/src/Grav/Common/Data/Blueprint.php b/system/src/Grav/Common/Data/Blueprint.php
index 24720c783..49b4aca06 100644
--- a/system/src/Grav/Common/Data/Blueprint.php
+++ b/system/src/Grav/Common/Data/Blueprint.php
@@ -25,6 +25,9 @@ class Blueprint extends BlueprintForm
     /** @var BlueprintSchema */
     protected $blueprintSchema;
 
+    /** @var array */
+    protected $defaults;
+
     public function setScope($scope)
     {
         $this->scope = $scope;
@@ -56,7 +59,11 @@ class Blueprint extends BlueprintForm
     {
         $this->initInternals();
 
-        return $this->blueprintSchema->getDefaults();
+        if (null === $this->defaults) {
+            $this->defaults = $this->blueprintSchema->getDefaults();
+        }
+
+        return $this->defaults;
     }
 
     /**
@@ -174,6 +181,7 @@ class Blueprint extends BlueprintForm
 
             $this->blueprintSchema->embed('', $this->items);
             $this->blueprintSchema->init();
+            $this->defaults = null;
         }
     }
 
diff --git a/system/src/Grav/Common/Debugger.php b/system/src/Grav/Common/Debugger.php
index 86b3d888c..3afce3798 100644
--- a/system/src/Grav/Common/Debugger.php
+++ b/system/src/Grav/Common/Debugger.php
@@ -21,6 +21,9 @@ use DebugBar\DebugBar;
 use DebugBar\JavascriptRenderer;
 use DebugBar\StandardDebugBar;
 use Grav\Common\Config\Config;
+use Grav\Common\Processors\ProcessorInterface;
+use Twig\Template;
+use Twig\TemplateWrapper;
 
 class Debugger
 {
@@ -44,7 +47,7 @@ class Debugger
     /** @var array */
     protected $timers = [];
 
-    /** @var string[] $deprecations */
+    /** @var array $deprecations */
     protected $deprecations = [];
 
     /** @var callable */
@@ -356,57 +359,183 @@ class Debugger
             return true;
         }
 
-        $backtrace = debug_backtrace(false);
+        // Figure out error scope from the error.
+        $scope = 'unknown';
+        if (stripos($errstr, 'grav') !== false) {
+            $scope = 'grav';
+        } elseif (strpos($errfile, '/twig/') !== false) {
+            $scope = 'twig';
+        } elseif (stripos($errfile, '/yaml/') !== false) {
+            $scope = 'yaml';
+        } elseif (strpos($errfile, '/vendor/') !== false) {
+            $scope = 'vendor';
+        }
+
+        // Clean up backtrace to make it more useful.
+        $backtrace = debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT);
 
         // Skip current call.
         array_shift($backtrace);
 
+        // Find yaml file where the error happened.
+        if ($scope === 'yaml') {
+            foreach ($backtrace as $current) {
+                if (isset($current['args'])) {
+                    foreach ($current['args'] as $arg) {
+                        if ($arg instanceof \SplFileInfo) {
+                            $arg = $arg->getPathname();
+                        }
+                        if (\is_string($arg) && preg_match('/.+\.(yaml|md)$/i', $arg)) {
+                            $errfile = $arg;
+                            $errline = 0;
+
+                            break 2;
+                        }
+                    }
+                }
+            }
+        }
+
+        // Filter arguments.
+        $cut = 0;
+        $previous = null;
+        foreach ($backtrace as $i => &$current) {
+            if (isset($current['args'])) {
+                $args = [];
+                foreach ($current['args'] as $arg) {
+                    if (\is_string($arg)) {
+                        $arg = "'" . $arg . "'";
+                        if (mb_strlen($arg) > 100) {
+                            $arg = 'string';
+                        }
+                    } elseif (\is_bool($arg)) {
+                        $arg = $arg ? 'true' : 'false';
+                    } elseif (\is_scalar($arg)) {
+                        $arg = $arg;
+                    } elseif (\is_object($arg)) {
+                        $arg = get_class($arg) . ' $object';
+                    } elseif (\is_array($arg)) {
+                        $arg = '$array';
+                    } else {
+                        $arg = '$object';
+                    }
+
+                    $args[] = $arg;
+                }
+                $current['args'] = $args;
+            }
+
+            $object = $current['object'] ?? null;
+            unset($current['object']);
+
+            $reflection = null;
+            if ($object instanceof TemplateWrapper) {
+                $reflection = new \ReflectionObject($object);
+                $property = $reflection->getProperty('template');
+                $property->setAccessible(true);
+                $object = $property->getValue($object);
+            }
+
+            if ($object instanceof Template) {
+                $file = $current['file'] ?? null;
+
+                if (preg_match('`(Template.php|TemplateWrapper.php)$`', $file)) {
+                    $current = null;
+                    continue;
+                }
+
+                $debugInfo = $object->getDebugInfo();
+
+                $line = 1;
+                if (!$reflection) {
+                    foreach ($debugInfo as $codeLine => $templateLine) {
+                        if ($codeLine <= $current['line']) {
+                            $line = $templateLine;
+                            break;
+                        }
+                    }
+                }
+
+                $src = $object->getSourceContext();
+                //$code = preg_split('/\r\n|\r|\n/', $src->getCode());
+                //$current['twig']['twig'] = trim($code[$line - 1]);
+                $current['twig']['file'] = $src->getPath();
+                $current['twig']['line'] = $line;
+
+                $prevFile = $previous['file'] ?? null;
+                if ($prevFile && $file === $prevFile) {
+                    $prevLine = $previous['line'];
+
+                    $line = 1;
+                    foreach ($debugInfo as $codeLine => $templateLine) {
+                        if ($codeLine <= $prevLine) {
+                            $line = $templateLine;
+                            break;
+                        }
+                    }
+
+                    //$previous['twig']['twig'] = trim($code[$line - 1]);
+                    $previous['twig']['file'] = $src->getPath();
+                    $previous['twig']['line'] = $line;
+                }
+
+                $cut = $i;
+            } elseif ($object instanceof ProcessorInterface) {
+                $cut = $cut ?: $i;
+                break;
+            }
+
+            $previous = &$backtrace[$i];
+        }
+        unset($current);
+
+        if ($cut) {
+            $backtrace = array_slice($backtrace, 0, $cut + 1);
+        }
+        $backtrace = array_values(array_filter($backtrace));
+
         // Skip vendor libraries and the method where error was triggered.
-        while ($current = array_shift($backtrace)) {
-            if (isset($current['file']) && strpos($current['file'], 'vendor') !== false) {
+        foreach ($backtrace as $i => $current) {
+            if (!isset($current['file'])) {
+                continue;
+            }
+            if (strpos($current['file'], '/vendor/') !== false) {
+                $cut = $i + 1;
                 continue;
             }
             if (isset($current['function']) && ($current['function'] === 'user_error' || $current['function'] === 'trigger_error')) {
-                $current = array_shift($backtrace);
+                $cut = $i + 1;
+                continue;
             }
 
             break;
         }
 
-        // Add back last call.
-        array_unshift($backtrace, $current);
-
-        // Filter arguments.
-        foreach ($backtrace as &$current) {
-            if (isset($current['args'])) {
-                $args = [];
-                foreach ($current['args'] as $arg) {
-                    if (\is_string($arg)) {
-                        $args[] = "'" . $arg . "'";
-                    } elseif (\is_bool($arg)) {
-                        $args[] = $arg ? 'true' : 'false';
-                    } elseif (\is_scalar($arg)) {
-                        $args[] = $arg;
-                    } elseif (\is_object($arg)) {
-                        $args[] = get_class($arg) . ' $object';
-                    } elseif (\is_array($arg)) {
-                        $args[] = '$array';
-                    } else {
-                        $args[] = '$object';
-                    }
-                }
-                $current['args'] = $args;
-            }
+        if ($cut) {
+            $backtrace = array_slice($backtrace, $cut);
         }
-        unset($current);
+        $backtrace = array_values(array_filter($backtrace));
 
-        $this->deprecations[] = [
+        $current = reset($backtrace);
+
+        // If the issue happened inside twig file, change the file and line to match that file.
+        $file = $current['twig']['file'] ?? '';
+        if ($file) {
+            $errfile = $file;
+            $errline = $current['twig']['line'] ?? 0;
+        }
+
+        $deprecation = [
+            'scope' => $scope,
             'message' => $errstr,
             'file' => $errfile,
             'line' => $errline,
             'trace' => $backtrace,
+            'count' => 1
         ];
 
+        $this->deprecations[] = $deprecation;
+
         // Do not pass forward.
         return true;
     }
@@ -431,38 +560,37 @@ class Debugger
 
     protected function getDepracatedMessage($deprecated)
     {
-        $scope = 'unknown';
-        if (stripos($deprecated['message'], 'grav') !== false) {
-            $scope = 'grav';
-        } elseif (!isset($deprecated['file'])) {
-            $scope = 'unknown';
-        } elseif (stripos($deprecated['file'], 'twig') !== false) {
-            $scope = 'twig';
-        } elseif (stripos($deprecated['file'], 'yaml') !== false) {
-            $scope = 'yaml';
-        } elseif (stripos($deprecated['file'], 'vendor') !== false) {
-            $scope = 'vendor';
-        }
+        $scope = $deprecated['scope'];
 
         $trace = [];
-        foreach ($deprecated['trace'] as $current) {
-            $class = $current['class'] ?? '';
-            $type = $current['type'] ?? '';
-            $function = $this->getFunction($current);
-            if (isset($current['file'])) {
-                $current['file'] = str_replace(GRAV_ROOT . '/', '', $current['file']);
+        if (isset($deprecated['trace'])) {
+            foreach ($deprecated['trace'] as $current) {
+                $class = $current['class'] ?? '';
+                $type = $current['type'] ?? '';
+                $function = $this->getFunction($current);
+                if (isset($current['file'])) {
+                    $current['file'] = str_replace(GRAV_ROOT . '/', '', $current['file']);
+                }
+
+                unset($current['class'], $current['type'], $current['function'], $current['args']);
+
+                if (isset($current['twig'])) {
+                    $trace[] = $current['twig'];
+                } else {
+                    $trace[] = ['call' => $class . $type . $function] + $current;
+                }
             }
-
-            unset($current['class'], $current['type'], $current['function'], $current['args']);
-
-            $trace[] = ['call' => $class . $type . $function] + $current;
         }
 
+        $array = [
+            'message' => $deprecated['message'],
+            'file' => $deprecated['file'],
+            'line' => $deprecated['line'],
+            'trace' => $trace
+        ];
+
         return [
-            [
-                'message' => $deprecated['message'],
-                'trace' => $trace
-            ],
+            array_filter($array),
             $scope
         ];
     }
@@ -473,6 +601,6 @@ class Debugger
             return '';
         }
 
-        return $trace['function'] . '(' . implode(', ', $trace['args']) . ')';
+        return $trace['function'] . '(' . implode(', ', $trace['args'] ?? []) . ')';
     }
 }
diff --git a/system/src/Grav/Common/User/FlexUser/User.php b/system/src/Grav/Common/User/FlexUser/User.php
index f97adfdb9..49084eb94 100644
--- a/system/src/Grav/Common/User/FlexUser/User.php
+++ b/system/src/Grav/Common/User/FlexUser/User.php
@@ -161,9 +161,9 @@ class User extends FlexObject implements UserInterface, MediaManipulationInterfa
      * @param string|null $separator
      * @return mixed
      */
-    public function value($name, $default = null, $separator = null)
+    public function getFormValue(string $name, $default = null, string $separator = null)
     {
-        $value = parent::value($name, null, $separator);
+        $value = parent::getFormValue($name, null, $separator);
 
         if ($name === 'avatar') {
             return $this->parseFileProperty($value);
diff --git a/system/src/Grav/Framework/Flex/Flex.php b/system/src/Grav/Framework/Flex/Flex.php
index de5ddcd26..8f47c46bf 100644
--- a/system/src/Grav/Framework/Flex/Flex.php
+++ b/system/src/Grav/Framework/Flex/Flex.php
@@ -63,7 +63,7 @@ class Flex implements \Countable
      */
     public function addDirectory(FlexDirectory $directory)
     {
-        $this->types[$directory->getType()] = $directory;
+        $this->types[$directory->getFlexType()] = $directory;
 
         return $this;
     }
diff --git a/system/src/Grav/Framework/Flex/FlexCollection.php b/system/src/Grav/Framework/Flex/FlexCollection.php
index a71ff604e..beacea8d8 100644
--- a/system/src/Grav/Framework/Flex/FlexCollection.php
+++ b/system/src/Grav/Framework/Flex/FlexCollection.php
@@ -87,7 +87,7 @@ class FlexCollection extends ObjectCollection implements FlexCollectionInterface
         parent::__construct($entries);
 
         if ($directory) {
-            $this->setFlexDirectory($directory)->setKey($directory->getType());
+            $this->setFlexDirectory($directory)->setKey($directory->getFlexType());
         }
     }
 
@@ -129,7 +129,7 @@ class FlexCollection extends ObjectCollection implements FlexCollectionInterface
      */
     public function getFlexType(): string
     {
-        return $this->_flexDirectory->getType();
+        return $this->_flexDirectory->getFlexType();
     }
 
     /**
@@ -245,7 +245,7 @@ class FlexCollection extends ObjectCollection implements FlexCollectionInterface
      * {@inheritdoc}
      * @see FlexCollectionInterface::render()
      */
-    public function render($layout = null, array $context = [])
+    public function render(string $layout = null, array $context = [])
     {
         if (null === $layout) {
             $layout = 'default';
diff --git a/system/src/Grav/Framework/Flex/FlexDirectory.php b/system/src/Grav/Framework/Flex/FlexDirectory.php
index d91b5564b..7b50a7eed 100644
--- a/system/src/Grav/Framework/Flex/FlexDirectory.php
+++ b/system/src/Grav/Framework/Flex/FlexDirectory.php
@@ -91,8 +91,19 @@ class FlexDirectory implements FlexAuthorizeInterface
 
     /**
      * @return string
+     * @deprecated 1.6 Use ->getFlexType() method instead.
      */
     public function getType(): string
+    {
+        user_error(__CLASS__ . '::' . __FUNCTION__ . '() is deprecated since Grav 1.6, use ->getFlexType() method instead', E_USER_DEPRECATED);
+
+        return $this->type;
+    }
+
+    /**
+     * @return string
+     */
+    public function getFlexType(): string
     {
         return $this->type;
     }
@@ -102,7 +113,7 @@ class FlexDirectory implements FlexAuthorizeInterface
      */
     public function getTitle(): string
     {
-        return $this->getBlueprintInternal()->get('title', ucfirst($this->getType()));
+        return $this->getBlueprintInternal()->get('title', ucfirst($this->getFlexType()));
     }
 
     /**
@@ -312,13 +323,13 @@ class FlexDirectory implements FlexAuthorizeInterface
                 if (Utils::isAdminPlugin()) {
                     $key = substr($key, 0, -1);
                 }
-                $cache = new DoctrineCache($gravCache->getCacheDriver(), 'flex-objects-' . $this->getType() . $key, $timeout);
+                $cache = new DoctrineCache($gravCache->getCacheDriver(), 'flex-objects-' . $this->getFlexType() . $key, $timeout);
             } catch (\Exception $e) {
                 /** @var Debugger $debugger */
                 $debugger = Grav::instance()['debugger'];
                 $debugger->addException($e);
 
-                $cache = new MemoryCache('flex-objects-' . $this->getType());
+                $cache = new MemoryCache('flex-objects-' . $this->getFlexType());
             }
 
             // Disable cache key validation.
diff --git a/system/src/Grav/Framework/Flex/FlexForm.php b/system/src/Grav/Framework/Flex/FlexForm.php
index 3e4d8265b..2629448ef 100644
--- a/system/src/Grav/Framework/Flex/FlexForm.php
+++ b/system/src/Grav/Framework/Flex/FlexForm.php
@@ -45,7 +45,7 @@ class FlexForm implements FlexFormInterface
     {
         $this->name = $name;
         $this->form = $form;
-        $uniqueId = $object->exists() ? $object->getStorageKey() : "{$object->getType()}:new";
+        $uniqueId = $object->exists() ? $object->getStorageKey() : "{$object->getFlexType()}:new";
         $this->setObject($object);
         $this->setId($this->getName());
         $this->setUniqueId(md5($uniqueId));
@@ -73,7 +73,7 @@ class FlexForm implements FlexFormInterface
         $object = $this->getObject();
         $name = $this->name ?: 'object';
 
-        return "flex-{$object->getType()}-{$name}";
+        return "flex-{$object->getFlexType()}-{$name}";
     }
 
     /**
@@ -101,6 +101,26 @@ class FlexForm implements FlexFormInterface
         return $value ?? $this->getObject()->value($name);
     }
 
+    public function getDefaultValue(string $name)
+    {
+        return $this->object->getDefaultValue($name);
+    }
+
+    /**
+     * @return array
+     */
+    public function getDefaultValues(): array
+    {
+        return $this->object->getDefaultValues();
+    }
+    /**
+     * @return string
+     */
+    public function getFlexType(): string
+    {
+        return $this->object->getFlexType();
+    }
+
     /**
      * @return FlexObjectInterface
      */
diff --git a/system/src/Grav/Framework/Flex/FlexIndex.php b/system/src/Grav/Framework/Flex/FlexIndex.php
index 77a2d85ac..b3b133edc 100644
--- a/system/src/Grav/Framework/Flex/FlexIndex.php
+++ b/system/src/Grav/Framework/Flex/FlexIndex.php
@@ -104,7 +104,7 @@ class FlexIndex extends ObjectIndex implements FlexCollectionInterface, FlexInde
      */
     public function getFlexType(): string
     {
-        return $this->_flexDirectory->getType();
+        return $this->_flexDirectory->getFlexType();
     }
 
     /**
@@ -171,7 +171,7 @@ class FlexIndex extends ObjectIndex implements FlexCollectionInterface, FlexInde
     {
         // Get storage keys for the objects.
         $keys = [];
-        $type = $this->_flexDirectory->getType() . '.obj:';
+        $type = $this->_flexDirectory->getFlexType() . '.obj:';
 
         foreach ($this->getEntries() as $key => $value) {
             $keys[$key] = $value['flex_key'] ?? $type . $value['storage_key'];
@@ -191,7 +191,7 @@ class FlexIndex extends ObjectIndex implements FlexCollectionInterface, FlexInde
             return $this;
         }
 
-        $type = $keyField === 'flex_key' ? $this->_flexDirectory->getType() . '.obj:' : '';
+        $type = $keyField === 'flex_key' ? $this->_flexDirectory->getFlexType() . '.obj:' : '';
         $entries = [];
         foreach ($this->getEntries() as $key => $value) {
             if (!isset($value['key'])) {
@@ -221,7 +221,7 @@ class FlexIndex extends ObjectIndex implements FlexCollectionInterface, FlexInde
      * {@inheritdoc}
      * @see FlexCollectionInterface::render()
      */
-    public function render($layout = null, array $context = [])
+    public function render(string $layout = null, array $context = [])
     {
         return $this->__call('render', [$layout, $context]);
     }
diff --git a/system/src/Grav/Framework/Flex/FlexObject.php b/system/src/Grav/Framework/Flex/FlexObject.php
index 4c8882187..ef8c4fd15 100644
--- a/system/src/Grav/Framework/Flex/FlexObject.php
+++ b/system/src/Grav/Framework/Flex/FlexObject.php
@@ -115,7 +115,7 @@ class FlexObject implements FlexObjectInterface, FlexAuthorizeInterface
      */
     public function getFlexType(): string
     {
-        return $this->_flexDirectory->getType();
+        return $this->_flexDirectory->getFlexType();
     }
 
     /**
@@ -186,7 +186,7 @@ class FlexObject implements FlexObjectInterface, FlexAuthorizeInterface
      */
     public function getFlexKey(): string
     {
-        return $this->_storage['flex_key'] ?? $this->_flexDirectory->getType() . '.obj:' . $this->getStorageKey();
+        return $this->_storage['flex_key'] ?? $this->_flexDirectory->getFlexType() . '.obj:' . $this->getStorageKey();
     }
 
     /**
@@ -357,7 +357,7 @@ class FlexObject implements FlexObjectInterface, FlexAuthorizeInterface
      * {@inheritdoc}
      * @see FlexObjectInterface::render()
      */
-    public function render($layout = null, array $context = [])
+    public function render(string $layout = null, array $context = [])
     {
         if (null === $layout) {
             $layout = 'default';
@@ -616,9 +616,50 @@ class FlexObject implements FlexObjectInterface, FlexAuthorizeInterface
 
     /**
      * {@inheritdoc}
-     * @see FlexObjectInterface::value()
+     * @see FlexObjectInterface::getDefaultValue()
      */
-    public function value($name, $default = null, $separator = null)
+    public function getDefaultValue(string $name, string $separator = null)
+    {
+        $separator = $separator ?: '.';
+        $path = explode($separator, $name) ?: [];
+        $offset = array_shift($path) ?? '';
+
+        $current = $this->getDefaultValues();
+
+        if (!isset($current[$offset])) {
+            return null;
+        }
+
+        $current = $current[$offset];
+
+        while ($path) {
+            $offset = array_shift($path);
+
+            if ((\is_array($current) || $current instanceof \ArrayAccess) && isset($current[$offset])) {
+                $current = $current[$offset];
+            } elseif (\is_object($current) && isset($current->{$offset})) {
+                $current = $current->{$offset};
+            } else {
+                return null;
+            }
+        };
+
+        return $current;
+    }
+
+    /**
+     * @return array
+     */
+    public function getDefaultValues(): array
+    {
+        return $this->getBlueprint()->getDefaults();
+    }
+
+    /**
+     * {@inheritdoc}
+     * @see FlexObjectInterface::getFormValue()
+     */
+    public function getFormValue(string $name, $default = null, string $separator = null)
     {
         if ($name === 'storage_key') {
             return $this->getStorageKey();
@@ -630,6 +671,19 @@ class FlexObject implements FlexObjectInterface, FlexAuthorizeInterface
         return $this->getNestedProperty($name, $default, $separator);
     }
 
+    /**
+     * @param string $name
+     * @param mixed|null $default
+     * @param string|null $separator
+     * @return mixed
+     *
+     * @deprecated 1.6 Use ->getFormValue() method instead.
+     */
+    public function value($name, $default = null, $separator = null)
+    {
+        return $this->getFormValue($name, $default, $separator);
+    }
+
     /**
      * Returns a string representation of this object.
      *
diff --git a/system/src/Grav/Framework/Flex/Interfaces/FlexCommonInterface.php b/system/src/Grav/Framework/Flex/Interfaces/FlexCommonInterface.php
index 89f12100f..482aef226 100644
--- a/system/src/Grav/Framework/Flex/Interfaces/FlexCommonInterface.php
+++ b/system/src/Grav/Framework/Flex/Interfaces/FlexCommonInterface.php
@@ -11,11 +11,8 @@ declare(strict_types=1);
 
 namespace Grav\Framework\Flex\Interfaces;
 
-use Grav\Framework\ContentBlock\ContentBlockInterface;
-use Grav\Framework\ContentBlock\HtmlBlock;
 use Grav\Framework\Flex\FlexDirectory;
-use Twig\Error\LoaderError;
-use Twig\Error\SyntaxError;
+use Grav\Framework\Interfaces\RenderInterface;
 
 /**
  * Defines common interface shared with both Flex Objects and Collections.
@@ -23,7 +20,7 @@ use Twig\Error\SyntaxError;
  * @used-by \Grav\Framework\Flex\FlexObject
  * @since 1.6
  */
-interface FlexCommonInterface
+interface FlexCommonInterface extends RenderInterface
 {
     /**
      * Get Flex Type of the object / collection.
@@ -64,22 +61,4 @@ interface FlexCommonInterface
      * @return string Returns cache checksum.
      */
     public function getCacheChecksum(): string;
-
-    /**
-     * Renders the object / collection.
-     *
-     * @example {% render object layout 'edit' with { limited: true } %}
-     * @example {% render collection layout 'list' %}
-     *
-     * @param string $layout Layout name.
-     * @param array $context Context given to the renderer.
-     *
-     * @return ContentBlockInterface|HtmlBlock Returns `HtmlBlock` containing the rendered output.
-     * @throws \Exception
-     * @throws \Throwable
-     * @throws LoaderError
-     * @throws SyntaxError
-     * @api
-     */
-    public function render($layout = null, array $context = []);
 }
diff --git a/system/src/Grav/Framework/Flex/Interfaces/FlexObjectInterface.php b/system/src/Grav/Framework/Flex/Interfaces/FlexObjectInterface.php
index d0f11f6e9..a10ee8447 100644
--- a/system/src/Grav/Framework/Flex/Interfaces/FlexObjectInterface.php
+++ b/system/src/Grav/Framework/Flex/Interfaces/FlexObjectInterface.php
@@ -129,7 +129,7 @@ interface FlexObjectInterface extends FlexCommonInterface, NestedObjectInterface
      * @throws \RuntimeException if object already exists.
      * @api
      */
-    public function create($key = null);
+    public function create(string $key = null);
 
     /**
      * Save object into the storage.
@@ -173,12 +173,36 @@ interface FlexObjectInterface extends FlexCommonInterface, NestedObjectInterface
     public function getForm(string $name = '', array $form = null);
 
     /**
-     * Form field compatibility.
+     * Returns default value suitable to be used in a form for the given property.
      *
-     * @param  string $name     Property name.
-     * @param  mixed  $default  Default value.
-     * @param  string $separator Optional nested property separator.
-     * @return mixed    Returns value of the field.
+     * @see FlexObjectInterface::getForm()
+     *
+     * @param  string $name         Property name.
+     * @param  string $separator    Optional nested property separator.
+     *
+     * @return mixed|null           Returns default value of the field, null if there is no default value.
      */
-    public function value($name, $default = null, $separator = null);
+    public function getDefaultValue(string $name, string $separator = null);
+
+    /**
+     * Returns default values suitable to be used in a form for the given property.
+     *
+     * @see FlexObjectInterface::getForm()
+     *
+     * @return array                Returns default values.
+     */
+    public function getDefaultValues(): array;
+
+    /**
+     * Returns raw value suitable to be used in a form for the given property.
+     *
+     * @see FlexObjectInterface::getForm()
+     *
+     * @param  string $name         Property name.
+     * @param  mixed  $default      Default value.
+     * @param  string $separator    Optional nested property separator.
+     *
+     * @return mixed                Returns value of the field.
+     */
+    public function getFormValue(string $name, $default = null, string $separator = null);
 }
diff --git a/system/src/Grav/Framework/Form/Traits/FormTrait.php b/system/src/Grav/Framework/Form/Traits/FormTrait.php
index 24d6a4b54..23f941093 100644
--- a/system/src/Grav/Framework/Form/Traits/FormTrait.php
+++ b/system/src/Grav/Framework/Form/Traits/FormTrait.php
@@ -113,6 +113,42 @@ trait FormTrait
         return $this->data[$name] ?? null;
     }
 
+    public function getDefaultValue(string $name)
+    {
+        $path = explode('.', $name) ?: [];
+        $offset = array_shift($path) ?? '';
+
+        $current = $this->getDefaultValues();
+
+        if (!isset($current[$offset])) {
+            return null;
+        }
+
+        $current = $current[$offset];
+
+        while ($path) {
+            $offset = array_shift($path);
+
+            if ((\is_array($current) || $current instanceof \ArrayAccess) && isset($current[$offset])) {
+                $current = $current[$offset];
+            } elseif (\is_object($current) && isset($current->{$offset})) {
+                $current = $current->{$offset};
+            } else {
+                return null;
+            }
+        };
+
+        return $current;
+    }
+
+    /**
+     * @return array
+     */
+    public function getDefaultValues(): array
+    {
+        return $this->getBlueprint()->getDefaults();
+    }
+
     /**
      * @param ServerRequestInterface $request
      * @return FormInterface|$this
diff --git a/system/src/Grav/Framework/Interfaces/RenderInterface.php b/system/src/Grav/Framework/Interfaces/RenderInterface.php
new file mode 100644
index 000000000..9185c1712
--- /dev/null
+++ b/system/src/Grav/Framework/Interfaces/RenderInterface.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @package    Grav\Framework\Interfaces
+ *
+ * @copyright  Copyright (C) 2015 - 2019 Trilby Media, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Framework\Interfaces;
+
+use Grav\Framework\ContentBlock\ContentBlockInterface;
+use Grav\Framework\ContentBlock\HtmlBlock;
+
+/**
+ * Defines common interface to render any object.
+ *
+ * @used-by \Grav\Framework\Flex\FlexObject
+ * @since 1.6
+ */
+interface RenderInterface
+{
+    /**
+     * Renders the object.
+     *
+     * @example $block = $object->render('custom', ['variable' => 'value']);
+     * @example {% render object layout 'custom' with { variable: 'value' } %}
+     *
+     * @param string|null $layout  Layout to be used.
+     * @param array|null  $context Extra context given to the renderer.
+     *
+     * @return ContentBlockInterface|HtmlBlock Returns `HtmlBlock` containing the rendered output.
+     * @api
+     */
+    public function render(string $layout = null, array $context = []);
+}
diff --git a/system/src/Grav/Framework/Object/Property/ArrayPropertyTrait.php b/system/src/Grav/Framework/Object/Property/ArrayPropertyTrait.php
index 2673f0c40..7092e15d5 100644
--- a/system/src/Grav/Framework/Object/Property/ArrayPropertyTrait.php
+++ b/system/src/Grav/Framework/Object/Property/ArrayPropertyTrait.php
@@ -95,7 +95,7 @@ trait ArrayPropertyTrait
      */
     protected function getElements()
     {
-        return $this->_elements;
+        return array_filter($this->_elements, function ($val) { return $val !== null; });
     }
 
     /**
diff --git a/system/src/Grav/Framework/Object/Property/ObjectPropertyTrait.php b/system/src/Grav/Framework/Object/Property/ObjectPropertyTrait.php
index efc0c7f05..5f8fdf0ac 100644
--- a/system/src/Grav/Framework/Object/Property/ObjectPropertyTrait.php
+++ b/system/src/Grav/Framework/Object/Property/ObjectPropertyTrait.php
@@ -183,7 +183,10 @@ trait ObjectPropertyTrait
 
         $elements = [];
         foreach ($properties as $offset => $value) {
-            $elements[$offset] = $this->offsetSerialize($offset, $value);
+            $serialized = $this->offsetSerialize($offset, $value);
+            if ($serialized !== null) {
+                $elements[$offset] = $this->offsetSerialize($offset, $value);
+            }
         }
 
         return $elements;