2000-12-11  Sven Neumann  <sven@gimp.org>

	* app/channel.c (channel_invalidate_previews): check for NULL pointer

	* app/fileops.c: if saving and loading images at the same time, the
	PDB obviously manages to mangle return values. By checking the
	validity of the returned image id we avoid to crash as described in
	bug #26788.

	* app/module_db.c: unload modules from the idle_loop as suggested
	by Austin in #5745.