Hi,
I am pretty sure that Drei gadgets are doing something naughty with input focus.
My X11 window manager has focus-follows-mouse (well, strictly, sloppy focus) for top-level windows. If I make a CLIM application containing a drei pane, then the application window will steal focus: if I have my mouse over the drei buffer, and then move it into a window which is above some portion of the drei pane, that window will get focus for a brief moment, and then the drei application will take it back...
Cheers,
Christophe