Speed problem dragging points

[mastupristi]

I have simplified as much as possible the event_filter example.
ev-filt.tar.gz
my purpose is to understand how this works, and then apply the overlay.
I have some questions, also unrelated to this issue.

but first of all I have to take a look deeply to the itemeditor example, and then I can try to apply overlay this example and the to my project.
Do you have any suggestion to make me get my goal quickly?

best regards
Max