Can't save anymore with Ctrl+S

Steps to reproduce:

• open a file or project, have a file open inside an editor
• change the file - but do not save it
• click on the toolbutton on the editor toolbar holding the document icon (directly before the document's name) with left mouse
• a menu should open up including an enabled "Save CurrentFileName   Ctrl+S"
• just click back into the editor without choosing anything from the menu
• from now on using Ctrl+S from the editor is broken (ambigous shortcut)