Wingpanel & indicators not navigable by keyboard

(Wasn't sure whether this issue belongs to the indicators or Wingpanel in general; please let me know if this is the wrong place for it!)

A minor annoyance I keep running into: I can't use the keyboard to navigate through Wingpanel indicator menus, or between indicators. (The network indicator is an exception—you can use tab to go through the list of available wireless networks, though not to connect/disconnect from them.)

Expected behaviour: on clicking on an indicator and bringing up its menu, you should be able to use the arrow/tab/space keys to select and perform actions on menu items, e. g. picking a different keyboard layout or opening up the settings application.