Have you tried getting the crash with all but compiler
turned off. Is this a plugin problem?
I think it's not only one problem, it's multiple problems.
I can reproduce the hang with SciTE when dragging text on linux, so that could mean that the problem is either in Scintilla, or GTK2.
BUT, I also get hangs when dragging toolbars/panels/tabs, so they could be the same bug, or different bugs, for instance in Scintilla, GTK, wxWidgets, wxAUI, C::B, ...