A better solution would be allow the "add notes", "add associated files" etc. feature in edit mode only, that way you can simply use QListView, custom delegates and custom editors etc..
Could you elaborate this a bit more? I am super new to Qt and sadly don't really understand what you mean here.
For my current understanding every ModelItem is represented through a delegate with a widget (wich is a custom widget containing other widgets (see image attached)) in the ListView.

Is there a way to have the whole widget as an editor and how can i create it? How do i make a widget being in "edit mode"?

Thanks,
René

Screen Shot 2015-02-23 at 11.00.17.png