Can someone elaborate on the specific nature of the changes in the auto-sandbox from build 1426 to 1451 ?
[If this has been explicitly answered elsewhere, a link to that would suffice,]
I would like to know also… as I’m not from the programmers team 
On default it actually seems worse to me, just rattled through my steam games and very common games such as GTA4 crash because a window pops up and the only option on it is terminate, no other options. You can change this in settings of course. But if I didn’t know this and I had just bought the program, it would be removed. All new titles seem to be white listed.
As I said you can change the settings by unticking some of the tick boxes. But out of the box, to me, it’s highly annoying.
What is your OS? There will be an update to v.7.0.1451 according to one of the Avast Team members next week some time that will affect XP users who are currently using SP2 instead of SP3. We encourage users to use the more recent version of software (example: SP3) to avoid malware.