Windows XP SP3
Avast 2015 RC1
Opera 12.17 Build 1863
Flash Player 15.0.0.152 (latest version)
Problem with the webshield.
When I open a web-page that is using flash, the webshield starts scanning but never stops.
Not even when I have closed all tabs.
Only after closing the browser entirely the webshield stops scanning.
The webshield definitely is causing pages (especially with flash and/or video content) loading slowly.
It makes video (like on Youtube) stuttering.
I have found out that avast keeps scanning while I have Mirc open although no conversations are taking place.
When I close Mirc or minimize it to the tray avast stops scanning.
I have tried to configure similar configuration as you (Mirc openend, streaming video in opera)
and result is “no shield activity”. See attachment.
Could you please test it one more again and take a screenshot of your avast statistics window?