GtkTreeView: make tree expanding/collapsing more robust
GtkTreeView: make tree expanding/collapsing more robust

gtk_grab_remove() *after* we did the expanding/collapsing, otherwise
grab_notify() might kick in and mess with our state. Fixes bug #675835.

johne53/MB3Gtk-2,johne53/MB3Gtk-2,Distrotech/gtk,Distrotech/gtk,johne53/MB3Gtk-2,johne53/MB3Gtk-2,johne53/MB3Gtk-2,Distrotech/gtk,Distrotech/gtk,Distrotech/gtk