Of the frequently reported "known problems", one bug is especially annoying because it is caused by nothing else but a call to a standard GDK function. For some reason, this call triggers an assert if xorg.conf has a "Composite" extension enabled. For details and pointers, see this bug's comments:
https://sourceforge.net/tracker/?func=detail&atid=604306&aid=1457003...
In brief, the trouble is caused by GDK calls from sp_dash_selector_menu_item_new in widgets/dash-selector.cpp
In Inkscape, this code did not change since Sodipodi times. It may be that we use the GDK functions in a wrong or deprecated way, or it may be that GDK itself is broken. This is the only place these functions are used in the entire codebase, and it's a bit embarassing to crash because of such trivial thing.
So, are there any GDK/GTK/X Window knowledgeable people in the audience who could help us fix this?