Docs: Add dropdowns framework guide stub.

docs/framework/guides/dropdowns.md

@@ -0,0 +1,103 @@
+---
+category: framework-ui
+order: 30
+---
+
+# Dropdowns
+
+## Creating Toolbar dropdown with SplitButton
+
+```js
+import ButtonView from '@ckeditor/ckeditor5-ui/src/button/buttonview';
+import Model from '@ckeditor/ckeditor5-ui/src/model';
+
+import addToolbarToDropdown from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/addtoolbartodropdown';
+import closeDropdownOnBlur from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/closedropdownonblur';
+import closeDropdownOnExecute from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/closedropdownonexecute';
+import createDropdownView from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/createdropdownview';
+import createSplitButtonForDropdown from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/createsplitbuttonfordropdown';
+import enableModelIfOneIsEnabled from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/enablemodelifoneisenabled';
+import focusDropdownContentsOnArrows from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/focusdropdowncontentsonarrows';
+
+const model = new Model( {
+	icon: 'some SVG',
+	tooltip: 'My dropdown'
+} );
+
+buttons.push( new ButtonView() );
+buttons.push( componentFactory.create( 'someExistingButton' ) );
+
+model.set( 'buttons', buttons );
+
+const splitButtonView = createSplitButtonForDropdown( model, locale );
+const dropdownView = createDropdownView( model, splitButtonView, locale );
+
+// Customize dropdown
+
+// This will enable toolbar button when any of button in dropdown is enabled.
+enableModelIfOneIsEnabled( model, buttons );
+
+// Make this a dropdown with toolbar inside dropdown panel.
+addToolbarToDropdown( dropdownView, model );
+
+// Add default behavior of dropdown
+closeDropdownOnBlur( dropdownView );
+closeDropdownOnExecute( dropdownView );
+focusDropdownContentsOnArrows( dropdownView );
+
+// Execute current action from dropdown's split button action button.
+dropdownView.buttonView.on( 'execute', () => {
+	editor.execute( 'command', { value: model.commandValue } );
+	editor.editing.view.focus();
+} );
+```
+
+## Creating ListView dropdown with standard button
+
+```js
+import Model from '@ckeditor/ckeditor5-ui/src/model';
+
+import addListViewToDropdown from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/addlistviewtodropdown';
+import closeDropdownOnBlur from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/closedropdownonblur';
+import closeDropdownOnExecute from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/closedropdownonexecute';
+import createDropdownView from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/createdropdownview';
+import createButtonForDropdown from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/createbuttonfordropdown';
+import focusDropdownContentsOnArrows from '@ckeditor/ckeditor5-ui/src/dropdown/helpers/focusdropdowncontentsonarrows';
+
+const items = [
+	new Model( {
+		label: 'Do Foo',
+		commandName: 'foo'
+	} ),
+	new Model( {
+		label: 'Do Bar',
+		commandName: 'bar'
+	} ),
+];
+
+// Create dropdown model.
+const model = new Model( {
+	icon: 'some icon SVG',
+	items
+} );
+
+const buttonView = createButtonForDropdown( model, locale );
+const dropdownView = createDropdownView( model, buttonView, locale );
+
+// Customize dropdown
+
+// This will enable toolbar button when any of button in dropdown is enabled.
+
+addListViewToDropdown( dropdownView, model, locale );
+
+// Add default behavior of dropdown
+closeDropdownOnBlur( dropdownView );
+closeDropdownOnExecute( dropdownView );
+focusDropdownContentsOnArrows( dropdownView );
+
+// Execute command when an item from the dropdown is selected.
+this.listenTo( dropdownView, 'execute', evt => {
+	editor.execute( evt.source.commandName );
+	editor.editing.view.focus();
+} );
+```