Video delay on zf2

It is really wierd, every time I'm trying to play a video on instagram,facebook,browser,etc...(except of YouTube) the video playing regulary few seconds and then the display stuck for 1-2 seconds while the voice is still playing so as a result a delay is created.
If anyone knows how to fix that I will be thankful.

Menu/Recents key delay - Only for single tap but not for double tap

There is a 1 or 2 sec delay when I press the Recents key and the recent apps show up. I used Gravity for Lollipop Xposed module to test changing it to double tap and it opens up immediately. The same happens for anything that is assigned to single press be it Menu, recent apps etc. All open immediately on double tap but have a delay with single press. Is there a way to remove this delay by editing some config file or by using some app/xposed module?