application launcher slowly to click.

I click and it takes 2 seconds to respond.

this problem with any plasma widget.
clock, notifications, wireless, sound, battery.

I have the same problem after migration to Plasma 5. Sometimes I have to click to claws-mail icon 4-5 times to popup its window. Sometimes reactions are too slow, sometimes it doesn't react at all for some time and then continue to react after 4-5 clicks to icon in panel. Video compositing doesn't work either in Plasma 5 in comparison with the latest KDE 4.