2004-01-18  Michael Natterer  <mitch@gimp.org>

	* app/core/gimpimage-undo-push.c (undo_pop_layer): removed broken
	code which tried to figure manually whether "alpha_changed" should
	be emitted. Instead, simply compare the return values of
	gimp_image_has_alpha() before and after adding/removing the
	layer. Fixes bug #131721.