rem: wDockSaveState(WScreen *scr)
add: wDockSaveState(WScreen *scr, proplist_t old_state)
context: wDockSaveState(WScreen *scr){    proplist_t dock_state;    dock_state = dockSaveState(scr->dock);    PLInsertDictionaryEntry(scr->session_state, dDock, dock_state);    PLRelease(dock_state);}