2004-11-16  Michael Natterer  <mitch@gimp.org>

	* app/core/gimpchannel-select.c
	* app/core/gimpchannel.c
	* app/core/gimpdrawable-desaturate.c
	* app/core/gimpdrawable-equalize.c
	* app/core/gimpdrawable-histogram.c
	* app/core/gimpdrawable-invert.c
	* app/core/gimpdrawable-levels.c
	* app/core/gimpdrawable-offset.c
	* app/core/gimpdrawable-stroke.c
	* app/core/gimpdrawable-transform.c
	* app/core/gimpdrawable.c
	* app/core/gimpitem-linked.c
	* app/core/gimpitem.c
	* app/core/gimplayer.c
	* app/core/gimpselection.c
	* app/paint/gimppaintcore-stroke.c
	* app/text/gimptextlayer.c: in all functions which somehow
	(explicitely or implicitely) touch undo, either g_return_if_fail()
	on gimp_item_is_attached() or simply don't push an undo step if
	feasible (e.g. for simple stuff like layer opacity).

	* tools/pdbgen/pdb/color.pdb
	* tools/pdbgen/pdb/drawable.pdb
	* tools/pdbgen/pdb/image.pdb
	* tools/pdbgen/pdb/layer.pdb
	* tools/pdbgen/pdb/paint_tools.pdb: let PDB wrappers fail
	accordingly so they don't run into the assertions added above.

	* app/pdb/color_cmds.c
	* app/pdb/drawable_cmds.c
	* app/pdb/image_cmds.c
	* app/pdb/layer_cmds.c
	* app/pdb/paint_tools_cmds.c: regenerated.