FormWidget filter = (FormWidget) getWidgetManager(session).getWidget("USERLIST_FILTER");
if (filter == null) {
filter = new FormWidget("USERLIST_FILTER", getLocale(request));
filter.setColumnCount(3);
filter.setShowLabelAtTop(true);
filter.addField(new StringField("username", "base.user.table.username", ""));
ComboBoxField groupField = new ComboBoxField("userGroup", "base.user.label.usergroupkey", "");
groupField.addOption("", "*");
for (UserGroup userGroup : getUserGroups()) {
groupField.addOption(userGroup.getId(), userGroup.getGroupKey());