1999-10-19  Michael Natterer  <mitch@gimp.org>

	* gimpcontext.[ch]: changed the "parent context" implementation:

	- Automatically connect/disconnect the "*_changed" signals when
	  changing the parent and when setting the "defined" flag of the
	  attributes.
	- Store the former *_defined booleans in a single guint32.
	- Added generic functions to set the "defined" flags of the
	  attributes and to copy attributes between contexts.

	The contexts now correctly handle disappearing images and
	displays, so we don't have to explicitly reset them any more.

	* context_manager.[ch]: adopted to the changed context
	implementation, connect to the user context's "tool_changed"
	signal to switch the per-tool contexts, don't connect to the
	"removed" signal of the image context.

	* brush_select.c
	* tool_options.c: use LayerModeEffects instead of int when calling
	gimp_context_set_paint_mode().

	* gdisplay.c: no need to reset the active display when deleting it
	because the context connects to the "destroy" signal of the shell
	now.

	* menus.c: a shortcut for the navigation window. Moved
	<Image>/Image/Colors/Desaturate before the separator.

	* tools.c: tools_select(): set the active tool of the user context
	instead of calling a special context manager function.