I'm thinking that the crash might be related to a combination of the video driver and something else then (coming from C::B, name it: C::B itself, wxWidgets, wxAUI, ...).
I'm using latest propietary Xorg ATI drivers, and certainly I use intensively other programs using GTK or wxWidgets (like VLC or Firefox), and never experienced any issue of this with another program.
Did I say that this most times happens when doing drag and drop on the panels?
The "strange cursor" that knue reffers about, it's the cursor in a DnD state.
BTW, dragging text also hangs C::B sometimes, altrough this is a Scintilla fault's because it happens in SciTE there too.
Dragging toolbars also hang C::B.
Of course, all of this happens sometimes, not always.