Threading issues

[Chris Seaton <chris chrisseaton com>]

I'm using threads with GTK+ for the first time and having trouble. The 
only time I start a new thread is for the (noticeably slow) file save 
and open routines.

When the user selects File -> Save the event handler disables the main 
window and starts a new thread. The entry point of that thread saves the 
file and then enables the main window again.

The save routine (running in the new thread) shows dialog boxes, both 
modal and modaless, but both transient on the main window. Is this 
simply not allowed?

The first dialog shown by the save thread is the file selector. The file 
selector shows ok, but when I close it I get

(cspassword:15291): Gdk-CRITICAL **: file gdkwindow-x11.c: line 1908 
(gdk_window_set_geometry_hints): assertion `window != NULL' failed

(cspassword:15291): Gdk-CRITICAL **: file gdkwindow-x11.c: line 1289 
(gdk_window_resize): assertion `window != NULL' failed
Xlib: unexpected async reply (sequence 0x5e7)!

The program is otherwise stable and the whole thing works when I keep 
the save routine in the main thread (running from the event handler). I 
don't think there could be any problems with critical sections here; 
with the main window disabled there is no way that the document would be 
modified during the save routine.

Thanks,

Chris Seaton