Undo Functionality in the Code Specification Editor
One of our students were complaining about the missing Undo(Strg+Z) functionality in the Code Specification editor. When he wrote some code and accidentally touched his touchpad, the whole code was gone and he counld not restore it by making an Undo.
(from redmine: issue id 1847, created on 2013-11-28, closed on 2014-07-29)