ENHANCEMENT Using chosen.js for group selection in Member->getCMSFields()

admin/javascript/LeftAndMain.js

@@ -363,9 +363,9 @@ jQuery.noConflict();
 		 * we can fix the height cropping.
 		 */
 		
-		$('.cms .field.dropdown').entwine({
+		$('.cms .field.dropdown, .cms .field.checkboxset').entwine({
 			onmatch: function() {
-				$(this).find("select:not(.no-chzn)").chosen();
+				$(this).find("select:not(.no-chzn)").data('placeholder', ' ').chosen();
 				$(this).addClass("has-chzn");
 				
 				this._super();

security/Member.php

@@ -1135,9 +1135,13 @@ class Member extends DataObject {
 		$fields->removeByName('Groups');
 
 		if(Permission::check('EDIT_PERMISSIONS')) {
-			$groupsField = new TreeMultiselectField('Groups', false, 'Group');
-			$fields->findOrMakeTab('Root.Groups', singleton('Group')->i18n_plural_name());
-			$fields->addFieldToTab('Root.Groups', $groupsField);
+			$groupsMap = DataList::create('Group')->map('ID', 'Breadcrumbs')->toArray();
+			asort($groupsMap);
+			$fields->addFieldToTab('Root.Main',
+				Object::create('CheckboxSetField', 'Groups', singleton('Group')->i18n_plural_name())
+					->setTemplate('CheckboxSetField_Select')
+					->setSource($groupsMap)
+			);
 
 			// Add permission field (readonly to avoid complicated group assignment logic).
 			// This should only be available for existing records, as new records start

templates/forms/CheckboxSetField_Select.ss

@@ -0,0 +1,11 @@
+<%-- Renders a CheckboxField with $multiple=true as a select element which can save into relations.--%>
+<%-- TODO Make relation saving available on ListboxField --%>
+<select id="$ID" class="$extraClass" name="$Name[]" multiple="true">
+	<% if Options.Count %>
+		<% control Options %>
+			<option class="$Class" value="$Value"<% if isChecked %> selected="selected"<% end_if %>>
+				$Title
+			</option> 
+		<% end_control %>
+	<% end_if %>
+</select>