Add object:state-changed:<STATE> events to event tree
requested to merge michaelweghorn/pyatspi2:michaelweghorn/add_state-changed_events_to_event_tree into master
Add the "object:state-changed:<STATE>" events for
the specific state changes to the event tree.
This e.g. allows to filter "object:state-changed" events
in Accerciser in a more fine-granular way to only
see those that are actually of interest.
GTK 3 sample app used for testing (sends dummy state changed events for all states): gtk3-sample-states.py
Fixes: accerciser#34 (closed)