Fix issue of events for setting cursor of treeview. - comp_dock_base.refresh() would set cursor, it cause an event. But, we don't want it. - The reason of the issue is that MBScene.show() is not monitored. So, we monitor it by move its body to do_show().

if X_BACKEND
SUBDIRS = calculator tank drag
if SH_TEXT
SUBDIRS += svg2code_ex dynamic menu
endif
endif