I have noticed the following behavioral changes since updating to the latest version of Avast (v2016).
I am running Win 8.1 using FF 28.0 and photofiltre form my graphics modifications. Now, both work just fine with Avast disabled; however, once I enable Avast, I have noticed the following changes:
FF28.0 - You cannot drag the right-hand scroll bar and gracefully move the slider up and down. It hangs and you have to regrab it (works great with Avast disabled).
FF28.0 - On any webpage, it is difficult to highlight text, right-click, and copy same (works great with Avast disabled).
In Photofiltre, when trying to utilize the draw a square and capture function, it doesn’t work. (works great with Avast disabled).
http://s10.postimg.org/pnf2egg6x/Screenshot_89.png
I’m sure there are more issues yet to be discovered; however, this is a show-stopper for me if not fixed. If yours works OK, then I’m pleased to know that as well.
Best regards,
plsrepli