Mark thumbnailview item as unselected when updating filter.

Change-Id: I10dd5ee79bf5c39bba4873633b3bf4438c703be0

sfx2/source/control/thumbnailview.cxx

@@ -1231,6 +1231,7 @@ void ThumbnailView::filterItems (const boost::function<bool (const ThumbnailView
                 }
 
                 pItem->show(false);
+                pItem->setSelection(false);
 
                 maItemStateHdl.Call(pItem);
             }