Editor: Closing a subview from code does not clean up properly and will lead to crash on opening the next subview

Can be reproduced by opening a table subview, left-click with the keyboard modifiers configured for "Edit and Close" and then opening another subview.

(RM-2564 from redmine: created on 2015-05-17 by Marc Zinnschlag, , closed on 2015-05-17 by Marc Zinnschlag)