function focusFirst(targetControl) {
			var navigationRoot = getNavigationRoot(targetControl);
			var focusElements = getFocusElements(navigationRoot.getEl());

			if (navigationRoot.settings.ariaRemember && "lastAriaIndex" in navigationRoot) {
				moveFocusToIndex(navigationRoot.lastAriaIndex, focusElements);
			} else {
				moveFocusToIndex(0, focusElements);
			}
		}
Focuses the first item in the specified targetControl element or the last aria index if the
navigation root has the ariaRemember option enabled.

@private
@param {tinymce.ui.Control} targetControl Target control to focus the first item in.