2002-03-17  Sven Neumann  <sven@gimp.org>

	* libgimpwidgets/gimpwidgets.[ch]: new function to set the sensitivity
	of an option_menu.

	* app/base/base-enums.[ch]: register and describe GimpHistogramChannel.

	* app/core/Makefile.am
	* app/core/core-enums.[ch]: build with gimp-mkenums, added core-enums.c
	to CVS, added descriptions for GimpPreviewSize.

	* app/display/Makefile.am
	* app/display/display-enums.[ch]: build with gimp-mkenums, added
	display-enums.c to CVS, added descriptions for GimpCursorMode.

	* app/gui/preferences-dialog.c: more GimpEnumMenus.

	* app/tools/gimpcurvestool.c
	* app/tools/gimphistogramtool.c
	* app/tools/gimplevelstool.c: use a GimpEnumMenu for the Channel menu.
	Allow alpha channel in HistogramView. These tools needs more work...