2001-07-20  Lutz Mller  <urc8@rz.uni-karlsruhe.de>

        * src/sheet-object-impl.h: Add the view as parameter to the virtual
        method set_active.
        * src/sheet-object-container.c:
        (sheet_object_container_set_active): New. Overrides above virtual and
        handles (de)activation of view frames.
        * src/sheet-control-gui-priv.h: Do not let the SheetControlGUI know
        about an active_object_frame - remove this variable.
        * src/sheet-control-gui.[c,h]:
        (scg_activate_view_frame),
        (scg_deactivate_view_frame): Removed. Now handled by the objects
        themselves through set_active virtual method.
        (scg_object_stop_editing),
        (scg_mode_edit_object): Adjust parameters for virtual method set_active.