2007-10-26  Sven Neumann  <sven@gimp.org>

	Reenabled update of the histogram while doing color corrections
	(bug 490182):

	* app/core/gimpviewable.[ch]: added new methods preview_freeze()
	and preview_thaw().

	* app/core/gimpimagemap.c
	(gimp_image_map_new): freeze the drawable preview.
	(gimp_image_map_dispose): thaw the  drawable preview.
	(gimp_image_map_do): update the drawable, not the image.

	* app/tools/gimpimagemaptool.c (gimp_image_map_tool_response): no
	need to invalidate the drawable preview any longer.

svn path=/trunk/; revision=23956