* configure.in: Check for libgnomecanvas.
* gtk/ColorSelectionDialog.custom: Create a button subclass which
contains a reference to the parent ColorSelectionDialog. Modify
properties to return this subclass instead of a regular
Gtk.Button.
* gtk/FileSelection.custom: Ditto.
* sample/test/TestFileSelection.cs (file_selection_ok):
Demonstrate the button subclass by destroying the parent dialog
when the ok button is clicked.
svn path=/trunk/gtk-sharp/; revision=6610
e14ce485dc