IE 11 slow painting

Question

Hello,
We have a web app that's currently experiencing long paint times when scrolling a list.  This isn't/wasn't the case in IE 10 - and it's fast in Chrome and Firefox.  But in IE 11, there are 2.5+ sec paint times while scrolling.  I've tried
everything I can think of and can't determine why it's so slow... turning off h/w accel, using dynatrace (had issues related to free version limitations), removing styles, removing event handlers, etc.  But no other info has been gained through all of
that other than it's really slow to paint the list (the area being scrolled) and the more stuff on there, the slower it is. Other browsers take about 200ms or less to paint the same area.
How can I find out more info about why IE 11 paint is so slow in this case, or why it's so much slower than IE 10, or... anything?
Thank you.

Answer 1

Ok, seems to potentially be related to a style in the background or parent element - once I removed all those, scrolling is fast again.
This may be related to conditional styles we left off for previous versions of IE but now that 11 reports itself as firefox, it's getting everything that FF gets but can't draw some of them as fast.
Now I just have to add things back in one at a time until I find out which style(s) it was.