2004-11-29  Sven Neumann  <sven@gimp.org>

	* libgimpwidgets/gimppreview.c (gimp_preview_toggle_callback):
	change the "update" property and notify listeners (in particular
	GimpDrawablePreview) before invalidating the preview. Plug-ins
	might (needlessly) look at the property to decide whether they
	need to redraw. Fixes bug #159816.

	* plug-ins/common/unsharp.c (preview_update): no need to look at
	the value of the "Preview" toggle. GimpPreview takes care this.