[FEATURE] EXT:form - Add element selector for text editors

Adds a new button to the text editors.
This splitbutton opens a list with available form elements.
If a form element is choosen, the form element identifier will be
inserted into the property text editor.

Resolves: #79442
Releases: master
Change-Id: If40114958311200348bde220f6cf62fb6365260b
Reviewed-on: https://review.typo3.org/51424

Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Bjoern Jacob <bjoern.jacob@tritum.de>
Tested-by: Bjoern Jacob <bjoern.jacob@tritum.de>
Tested-by: Andreas Steiger <typo3@andreassteiger.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>

Build/Resources/Public/Less/form.less

@@ -24,6 +24,7 @@
 @text-color: #000;
 @btn-default-bg: #eee;
 @btn-default-border: #bbb;
+@line-height-base: 1.5;
 
 // /Build/Resources/Public/Less/Component/module.less
 @module-docheader-height: 65px;
@@ -55,6 +56,7 @@
 
 .fade-out-gradient-effect-bottom (@color, @gradient-start-height, @gradient-height) {
   &:before, &:after {
+    z-index: 1;
     display: block;
     content: '';
     position: absolute;
@@ -112,7 +114,7 @@
     text-decoration: none;
   }
   ol,
-  ul {
+  ul:not(.dropdown-menu) {
     list-style: none;
     padding: 0;
   }
@@ -270,6 +272,12 @@
       vertical-align: top;
     }
   }
+  .icon-size-small {
+    line-height: @line-height-base;
+  }
+  .input-group-btn {
+    position: static;
+  }
   .t3-form-remove-element-button {
     position: absolute;
     top: 90px;
@@ -285,6 +293,16 @@
       cursor: pointer;
     }
   }
+  .t3-form-dropdown-buttons.open {
+    position: static;
+    .dropdown-menu {
+      width: 100%;
+      a {
+        overflow: hidden;
+        text-overflow: ellipsis;
+      }
+    }
+  }
 }
 
 //
@@ -660,10 +678,7 @@
           right: -1px;
         }
         .dropdown-menu {
-          left: auto;
-          left: initial;
           min-width: initial;
-          right: 0;
           padding-left: 0;
           padding-right: 0;
           background-color: darken(@brand-primary, 10%);
@@ -723,7 +738,7 @@
       height: 32px;
       padding: 0.6em;
       font-size: 12px;
-      line-height: 1.5;
+      line-height: @line-height-base;
       background-image: none;
       border: 1px solid @module-docheader-border;
       border-radius: 2px;
@@ -784,7 +799,7 @@
 }
 
 .meta-label {
-  z-index: 1;
+  z-index: 2;
   position: absolute;
   bottom: 1em;
   left: 5.5em;
@@ -896,6 +911,9 @@
       path {
         fill: @brand-danger;
       }
+      &:hover {
+        background: lighten(@brand-danger, 30%);
+      }
     }
   }
 }

typo3/sysext/core/Documentation/Changelog/master/Feature-79442-EXTform-AddElementSelectorForTextEditors.rst

+.. include:: ../../Includes.txt
+
+==================================================================
+Feature: #79442 - EXT:form - add element selector for text editors
+==================================================================
+
+See :issue:`79442`
+
+Description
+===========
+
+A new button has been added to the text editors of the form editor. Clicking on this button opens an overlay with available form elements of the current form. The user has the possibility to choose one of these form elements. The process adds the dynamic identifier (e.g. "{text-1}" to the current tex editor field.
+
+.. index:: Backend, ext:form
\ No newline at end of file

typo3/sysext/form/Configuration/Yaml/FormEditorSetup.yaml

@@ -143,6 +143,8 @@ TYPO3:
                 modalRemoveElementLastAvailablePageFlashMessageTitle: 'formEditor.modals.removeElement.lastAvailablePageFlashMessageTitle'
                 modalRemoveElementLastAvailablePageFlashMessageMessage: 'formEditor.modals.removeElement.lastAvailablePageFlashMessageMessage'
 
+                inspectorEditorFormElementSelectorNoElements: 'formEditor.inspector.editor.formelement_selector.no_elements'
+
                 paginationTitle: 'formEditor.pagination.title'
 
                 iconIdentifier: 'content-elements-mailform'
@@ -926,6 +928,7 @@ TYPO3:
                 templateName: 'Inspector-TextEditor'
                 label: 'formEditor.elements.Form.finisher.EmailToSender.editor.subject.label'
                 propertyPath: 'options.subject'
+                enableFormelementSelectionButton: true
                 propertyValidators:
                   10: 'NotEmpty'
                   20: 'FormElementIdentifierWithinCurlyBracesInclusive'
@@ -934,6 +937,7 @@ TYPO3:
                 templateName: 'Inspector-TextEditor'
                 label: 'formEditor.elements.Form.finisher.EmailToSender.editor.recipientAddress.label'
                 propertyPath: 'options.recipientAddress'
+                enableFormelementSelectionButton: true
                 propertyValidatorsMode: 'OR'
                 propertyValidators:
                   10: 'NaiveEmail'
@@ -943,11 +947,15 @@ TYPO3:
                 templateName: 'Inspector-TextEditor'
                 label: 'formEditor.elements.Form.finisher.EmailToSender.editor.recipientName.label'
                 propertyPath: 'options.recipientName'
+                enableFormelementSelectionButton: true
+                propertyValidators:
+                  10: 'FormElementIdentifierWithinCurlyBracesInclusive'
               500:
                 identifier: 'senderAddress'
                 templateName: 'Inspector-TextEditor'
                 label: 'formEditor.elements.Form.finisher.EmailToSender.editor.senderAddress.label'
                 propertyPath: 'options.senderAddress'
+                enableFormelementSelectionButton: true
                 propertyValidatorsMode: 'OR'
                 propertyValidators:
                   10: 'NaiveEmail'
@@ -957,11 +965,15 @@ TYPO3:
                 templateName: 'Inspector-TextEditor'
                 label: 'formEditor.elements.Form.finisher.EmailToSender.editor.senderName.label'
                 propertyPath: 'options.senderName'
+                enableFormelementSelectionButton: true
+                propertyValidators:
+                  10: 'FormElementIdentifierWithinCurlyBracesInclusive'
               700:
                 identifier: 'replyToAddress'
                 templateName: 'Inspector-TextEditor'
                 label: 'formEditor.elements.Form.finisher.EmailToSender.editor.replyToAddress.label'
                 propertyPath: 'options.replyToAddress'
+                enableFormelementSelectionButton: true
                 propertyValidatorsMode: 'OR'
                 propertyValidators:
                   10: 'NaiveEmailOrEmpty'
@@ -971,6 +983,7 @@ TYPO3:
                 templateName: 'Inspector-TextEditor'
                 label: 'formEditor.elements.Form.finisher.EmailToSender.editor.carbonCopyAddress.label'
                 propertyPath: 'options.carbonCopyAddress'
+                enableFormelementSelectionButton: true
                 propertyValidatorsMode: 'OR'
                 propertyValidators:
                   10: 'NaiveEmailOrEmpty'
@@ -980,6 +993,7 @@ TYPO3:
                 templateName: 'Inspector-TextEditor'
                 label: 'formEditor.elements.Form.finisher.EmailToSender.editor.blindCarbonCopyAddress.label'
                 propertyPath: 'options.blindCarbonCopyAddress'
+                enableFormelementSelectionButton: true
                 propertyValidatorsMode: 'OR'
                 propertyValidators:
                   10: 'NaiveEmailOrEmpty'

typo3/sysext/form/Resources/Private/Backend/Templates/FormEditor/Inspector/TextEditor.html

+{namespace core = TYPO3\CMS\Core\ViewHelpers}
+
 <div class="form-editor">
     <div class="t3-form-control-group form-group">
         <label><span data-template-property="label" /></label>
-        <div class="t3-form-controls" data-identifier="inspectorEditorControlsWrapper">
-            <input type="text" value="" data-template-property="propertyPath" class="form-control">
-            <span data-template-property="fieldExplanationText" />
-            <span data-template-property="validationErrors" />
+        <div class="input-group" data-identifier="inspectorEditorControlsGroup">
+            <div class="t3-form-controls" data-identifier="inspectorEditorControlsWrapper">
+                <input type="text" value="" data-template-property="propertyPath" class="form-control">
+            </div>
+
+            <span class="input-group-btn" role="group" data-identifier="inspectorEditorFormElementSelectorControlsWrapper">
+                <span class="btn-group t3-form-dropdown-buttons" data-identifier="inspectorEditorFormElementSelectorSplitButtonContainer">
+                   <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" aria-expanded="false" title="{f:translate(key: 'LLL:EXT:form/Resources/Private/Language/Database.xlf:formEditor.inspector.editor.formelement_selector.title')}">
+                       <core:icon identifier="t3-form-icon-form-element-selector" />
+                       <span class="caret"></span>
+                       <span class="sr-only">Toggle Dropdown</span>
+                   </button>
+                   <ul class="dropdown-menu dropdown-menu-right" data-identifier="inspectorEditorFormElementSelectorSplitButtonListContainer"></ul>
+                </span>
+            </span>
         </div>
+        <span data-template-property="fieldExplanationText" />
+        <span data-template-property="validationErrors" />
     </div>
 </div>
\ No newline at end of file

typo3/sysext/form/Resources/Private/Backend/Templates/FormEditor/Stage/_ElementToolbar.html

@@ -12,7 +12,7 @@
                    <span class="caret"></span>
                    <span class="sr-only">Toggle Dropdown</span>
                </button>
-               <ul class="dropdown-menu">
+               <ul class="dropdown-menu dropdown-menu-right">
                   <li data-no-sorting>
                      <a href="#" data-identifier="stageElementToolbarNewElementSplitButtonInside">
                          <core:icon identifier="t3-form-icon-insert-in" alternativeMarkupIdentifier="inline" />

typo3/sysext/form/Resources/Private/Language/Database.xlf

@@ -685,6 +685,13 @@
             <trans-unit id="formEditor.stage.toolbar.new_element.after" xml:space="preserve">
                 <source>After</source>
             </trans-unit>
+
+            <trans-unit id="formEditor.inspector.editor.formelement_selector.title" xml:space="preserve">
+                <source>Insert formelement identifier</source>
+            </trans-unit>
+            <trans-unit id="formEditor.inspector.editor.formelement_selector.no_elements" xml:space="preserve">
+                <source>No elements available</source>
+            </trans-unit>
         </body>
     </file>
 </xliff>

typo3/sysext/form/Resources/Public/Css/form.css

@@ -22,7 +22,7 @@
   text-decoration: none;
 }
 .t3-form-x-component ol,
-.t3-form-x-component ul {
+.t3-form-x-component ul:not(.dropdown-menu) {
   list-style: none;
   padding: 0;
 }
@@ -162,6 +162,12 @@
 #t3-form-inspector h4 span[data-template-property="label"] {
   vertical-align: top;
 }
+#t3-form-inspector .icon-size-small {
+  line-height: 1.5;
+}
+#t3-form-inspector .input-group-btn {
+  position: static;
+}
 #t3-form-inspector .t3-form-remove-element-button {
   position: absolute;
   top: 90px;
@@ -175,6 +181,16 @@
 #t3-form-inspector .t3-form-inspector-editor-requiredValidator label {
   cursor: pointer;
 }
+#t3-form-inspector .t3-form-dropdown-buttons.open {
+  position: static;
+}
+#t3-form-inspector .t3-form-dropdown-buttons.open .dropdown-menu {
+  width: 100%;
+}
+#t3-form-inspector .t3-form-dropdown-buttons.open .dropdown-menu a {
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
 .t3-form-add-collection-element {
   padding-bottom: 1em;
 }
@@ -407,6 +423,7 @@
 }
 #t3-form-stage-container.t3-form-stage-viewmode-abstract .t3-form-element-info:before,
 #t3-form-stage-container.t3-form-stage-viewmode-abstract .t3-form-element-info:after {
+  z-index: 1;
   display: block;
   content: '';
   position: absolute;
@@ -472,6 +489,7 @@
 }
 #t3-form-stage-container.t3-form-stage-viewmode-abstract .t3-form-validator-info .t3-form-validator-list:before,
 #t3-form-stage-container.t3-form-stage-viewmode-abstract .t3-form-validator-info .t3-form-validator-list:after {
+  z-index: 1;
   display: block;
   content: '';
   position: absolute;
@@ -553,10 +571,7 @@
   right: -1px;
 }
 #t3-form-stage-container.t3-form-stage-viewmode-abstract #t3-form-stage .t3-form-form-element-selected .btn-toolbar-container .dropdown-menu {
-  left: auto;
-  left: initial;
   min-width: initial;
-  right: 0;
   padding-left: 0;
   padding-right: 0;
   background-color: #005db3;
@@ -697,7 +712,7 @@
   display: none;
 }
 .meta-label {
-  z-index: 1;
+  z-index: 2;
   position: absolute;
   bottom: 1em;
   left: 5.5em;
@@ -798,6 +813,9 @@
 #t3-form-inspector-panels .t3-form-validation-errors.t3-form-collection-element .t3-form-collection-element-remove-button path {
   fill: #c83c3c;
 }
+#t3-form-inspector-panels .t3-form-validation-errors.t3-form-collection-element .t3-form-collection-element-remove-button:hover {
+  background: #eab3b3;
+}
 .form-editor-loading-spinner {
   width: 150px;
   margin: 5em auto 0;

typo3/sysext/form/Resources/Public/Images/form-element-selector.svg

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Generator: Adobe Illustrator 21.0.2, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
+<svg version="1.1" id="Ebene_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
+	 viewBox="0 0 16 16" style="enable-background:new 0 0 16 16;" xml:space="preserve">
+<polygon points="11,8 8,8 8,5 7,5 7,8 4,8 4,9 7,9 7,12 8,12 8,9 11,9 "/>
+<path d="M2,9c0-0.6-0.4-1-1-1c0.6,0,1-0.4,1-1V3h1.8V2H2C1.4,2,1,2.4,1,3v4C0.4,7,0,7.4,0,8l0,0c0,0.6,0.4,1,1,1v4c0,0.6,0.4,1,1,1
+	h1.8v-1H2V9z"/>
+<path d="M14,7V3c0-0.6-0.4-1-1-1h-1.8v1H13v4c0,0.6,0.4,1,1,1c-0.6,0-1,0.4-1,1v4h-1.8v1H13c0.6,0,1-0.4,1-1V9c0.6,0,1-0.4,1-1l0,0
+	C15,7.4,14.6,7,14,7z"/>
+</svg>

typo3/sysext/form/Resources/Public/JavaScript/Backend/FormEditor.js

@@ -800,6 +800,15 @@ define(['jquery',
                 );
             };
 
+            /**
+             * @public
+             *
+             * @return object
+             */
+            function getNonCompositeNonToplevelFormElements() {
+                return _getRepository().getNonCompositeNonToplevelFormElements();
+            };
+
             /**
              * @public
              *
@@ -1051,6 +1060,7 @@ define(['jquery',
                 findEnclosingCompositeFormElementWhichIsNotOnTopLevel: findEnclosingCompositeFormElementWhichIsNotOnTopLevel,
                 isRootFormElementSelected: isRootFormElementSelected,
                 getLastFormElementWithinParentFormElement: getLastFormElementWithinParentFormElement,
+                getNonCompositeNonToplevelFormElements: getNonCompositeNonToplevelFormElements,
 
                 getFormElementDefinitionByType: getFormElementDefinitionByType,
                 getFormElementDefinition: getFormElementDefinition,

typo3/sysext/form/Resources/Public/JavaScript/Backend/FormEditor/Core.js

@@ -1309,6 +1309,35 @@ define(['jquery'], function($) {
                 return formElement;
             };
 
+            /**
+             * @return object
+             */
+            function getNonCompositeNonToplevelFormElements() {
+                var collect, nonCompositeNonToplevelFormElements;
+
+                collect = function(formElement) {
+                    var formElements, formElementTypeDefinition;
+                    utility().assert('object' === $.type(formElement), 'Invalid parameter "formElement"', 1475364961);
+
+                    formElementTypeDefinition = repository().getFormEditorDefinition('formElements', formElement.get('type'));
+
+                    if (!formElementTypeDefinition['_isTopLevelFormElement'] && !formElementTypeDefinition['_isCompositeFormElement']) {
+                        nonCompositeNonToplevelFormElements.push(formElement);
+                    }
+
+                    formElements = formElement.get('renderables');
+                    if ('array' === $.type(formElements)) {
+                        for (var i = 0, len = formElements.length; i < len; ++i) {
+                            collect(formElements[i]);
+                        }
+                    }
+                };
+
+                nonCompositeNonToplevelFormElements = [];
+                collect(getRootFormElement());
+                return nonCompositeNonToplevelFormElements;
+            };
+
             /**
              * @param string identifier
              * @returl bool
@@ -1610,6 +1639,7 @@ define(['jquery'], function($) {
                 findEnclosingCompositeFormElementWhichIsNotOnTopLevel: findEnclosingCompositeFormElementWhichIsNotOnTopLevel,
                 findEnclosingCompositeFormElementWhichIsOnTopLevel: findEnclosingCompositeFormElementWhichIsOnTopLevel,
                 getIndexForEnclosingCompositeFormElementWhichIsOnTopLevelForFormElement: getIndexForEnclosingCompositeFormElementWhichIsOnTopLevelForFormElement,
+                getNonCompositeNonToplevelFormElements: getNonCompositeNonToplevelFormElements,
 
                 getNextFreeFormElementIdentifier: getNextFreeFormElementIdentifier,
                 isFormElementIdentifierUsed: isFormElementIdentifierUsed,

typo3/sysext/form/Resources/Public/JavaScript/Backend/FormEditor/InspectorComponent.js

@@ -49,6 +49,7 @@ define(['jquery',
                 collectionElement: 't3-form-collection-element',
                 finisherEditorPrefix: 't3-form-inspector-finishers-editor-',
                 inspectorEditor: 'form-editor',
+                inspectorInputGroup: 'input-group',
                 validatorEditorPrefix: 't3-form-inspector-validators-editor-'
             },
             domElementDataAttributeNames: {
@@ -58,8 +59,13 @@ define(['jquery',
             },
             domElementDataAttributeValues: {
                 collapse: 'actions-view-table-expand',
+                editorControlsInputGroup: 'inspectorEditorControlsGroup',
                 editorControlsWrapper: 'inspectorEditorControlsWrapper',
                 formElementHeaderEditor: 'inspectorFormElementHeaderEditor',
+                formElementSelectorControlsWrapper: 'inspectorEditorFormElementSelectorControlsWrapper',
+                formElementSelectorSplitButtonContainer: 'inspectorEditorFormElementSelectorSplitButtonContainer',
+                formElementSelectorSplitButtonListContainer: 'inspectorEditorFormElementSelectorSplitButtonListContainer',
+                iconNotAvailable: 'actions-message-error-close',
                 iconPage: 'apps-pagetree-page-default',
                 iconTtContent: 'mimetypes-x-content-text',
                 inspector: 'inspector',
@@ -1066,6 +1072,8 @@ define(['jquery',
 
             getHelper().getTemplatePropertyDomElement('propertyPath', editorHtml).val(propertyData);
 
+            renderFormElementSelectorEditorAddition(editorConfiguration, editorHtml, propertyPath);
+
             getHelper().getTemplatePropertyDomElement('propertyPath', editorHtml).on('keyup paste', function() {
                 getCurrentlySelectedFormElement().set(propertyPath, $(this).val());
                 _validateCollectionElement(propertyPath, editorHtml);
@@ -1705,6 +1713,115 @@ define(['jquery',
             });
         };
 
+        /**
+         * @public
+         *
+         * @param object editorConfiguration
+         * @param object editorHtml
+         * @param string propertyPath
+         * @return void
+         * @throws 1484574704
+         * @throws 1484574705
+         * @throws 1484574706
+         */
+        function renderFormElementSelectorEditorAddition(editorConfiguration, editorHtml, propertyPath) {
+            var nonCompositeNonToplevelFormElements, formElementSelectorControlsWrapper, formElementSelectorSplitButtonListContainer, itemTemplate;
+
+            assert(
+                'object' === $.type(editorConfiguration),
+                'Invalid parameter "editorConfiguration"',
+                1484574704
+            );
+            assert(
+                'object' === $.type(editorHtml),
+                'Invalid parameter "editorHtml"',
+                1484574705
+            );
+            assert(
+                getUtility().isNonEmptyString(propertyPath),
+                'Invalid parameter "propertyPath"',
+                1484574706
+            );
+
+            formElementSelectorControlsWrapper = $(
+                getHelper().getDomElementDataIdentifierSelector('formElementSelectorControlsWrapper'), editorHtml
+            );
+
+            if (editorConfiguration['enableFormelementSelectionButton'] === true) {
+                if (formElementSelectorControlsWrapper.length === 0) {
+                    return;
+                }
+
+                formElementSelectorSplitButtonListContainer = $(
+                    getHelper().getDomElementDataIdentifierSelector('formElementSelectorSplitButtonListContainer'), editorHtml
+                );
+
+                formElementSelectorSplitButtonListContainer.off().empty();
+                nonCompositeNonToplevelFormElements = getFormEditorApp().getNonCompositeNonToplevelFormElements();
+
+                if (nonCompositeNonToplevelFormElements.length === 0) {
+                    Icons.getIcon(
+                        getHelper().getDomElementDataAttributeValue('iconNotAvailable'),
+                        Icons.sizes.small,
+                        null,
+                        Icons.states.default
+                    ).done(function(icon) {
+                        itemTemplate = $('<li data-no-sorting>'
+                                         +   '<a href="#"></a>'
+                                     +   '</li>');
+
+                        itemTemplate
+                            .append($(icon))
+                            .append(' ' + getFormElementDefinition(getRootFormElement(), 'inspectorEditorFormElementSelectorNoElements'));
+                        formElementSelectorSplitButtonListContainer.append(itemTemplate);
+                    });
+                } else {
+                    for (var i = 0, len = nonCompositeNonToplevelFormElements.length; i < len; ++i) {
+                        var nonCompositeNonToplevelFormElement;
+
+                        nonCompositeNonToplevelFormElement = nonCompositeNonToplevelFormElements[i];
+                        Icons.getIcon(
+                            getFormElementDefinition(nonCompositeNonToplevelFormElement, 'iconIdentifier'),
+                            Icons.sizes.small,
+                            null,
+                            Icons.states.default
+                        ).done(function(icon) {
+                            itemTemplate = $('<li data-no-sorting>'
+                                             +   '<a href="#" data-formelement-identifier="' + nonCompositeNonToplevelFormElement.get('identifier') + '">'
+                                             +   '</a>'
+                                         +   '</li>');
+
+                            $('[data-formelement-identifier="' + nonCompositeNonToplevelFormElement.get('identifier') + '"]', itemTemplate)
+                                .append($(icon))
+                                .append(' ' + nonCompositeNonToplevelFormElements[i].get('label'));
+
+                            $('a', itemTemplate).on('click', function() {
+                                var propertyData;
+
+                                propertyData = getCurrentlySelectedFormElement().get(propertyPath);
+
+                                if (propertyData.length === 0) {
+                                    propertyData = '{' + $(this).attr('data-formelement-identifier') + '}';
+                                } else {
+                                    propertyData = propertyData + ' ' + '{' + $(this).attr('data-formelement-identifier') + '}';
+                                }
+
+                                getCurrentlySelectedFormElement().set(propertyPath, propertyData);
+                                getHelper().getTemplatePropertyDomElement('propertyPath', editorHtml).val(propertyData);
+                                _validateCollectionElement(propertyPath, editorHtml);
+                            });
+
+                            formElementSelectorSplitButtonListContainer.append(itemTemplate);
+                        });
+                    }
+                }
+            } else {
+                $(getHelper().getDomElementDataIdentifierSelector('editorControlsInputGroup'), editorHtml)
+                    .removeClass(getHelper().getDomElementClassName('inspectorInputGroup'));
+                formElementSelectorControlsWrapper.off().empty().remove();
+            }
+        }
+
         /**
          * @public
          *
@@ -1771,6 +1888,7 @@ define(['jquery',
             renderCollectionElementSelectionEditor: renderCollectionElementSelectionEditor,
             renderEditors: renderEditors,
             renderFormElementHeaderEditor: renderFormElementHeaderEditor,
+            renderFormElementSelectorEditorAddition: renderFormElementSelectorEditorAddition,
             renderPropertyGridEditor: renderPropertyGridEditor,
             renderRemoveElementEditor: renderRemoveElementEditor,
             renderRequiredValidatorEditor: renderRequiredValidatorEditor,

typo3/sysext/form/ext_localconf.php

@@ -40,6 +40,7 @@ call_user_func(function () {
         'fieldset',
         'file-upload',
         'finisher',
+        'form-element-selector',
         'image-upload',
         'insert-after',
         'insert-in',