I doubt that Flash is causing the firefox.exe crashes, at least in my case. firefox.exe crashes several times a day, even when there is no active Flash content in any of the tabs, and when none of the open tabs contain any Flash content at all. It also crashes when Avant is running in the background and even when I'm away from the computer (I'm the only user). I'll bring Avant to the foreground, or I'll return to the computer, and I'll find that firefox.exe crashed while it was in the background or while I was away (the Something went wrong... message is shown for all open tabs, and firefox.exe is no longer listed in the process list in Task Manager). Avant itself is unaffected, as the Avant UI components still function normally.
As I've reported before, the firefox.exe crashes seem to be directly related to an increasing lack of responsiveness to mouse and keyboard actions, such as a delayed response to hovering the mouse cursor over a link (cursor does not change to the pointing hand), delayed response to mouse clicks, delayed response when typing text, etc., within web pages. As time passes during the current firefox.exe session, the delays become more and more pronounced
until firefox.exe finally freezes (no response to anything in any of the tabs), and then (after a few seconds to a few minutes) firefox.exe terminates (the Avant UI itself is unaffected throughout). I've been unable to correlate the unresponsiveness to memory or CPU usage or to any other aspect of system operation. Even when the firefox.exe tabs are at the point where the freeze is about to occur or has occurred, memory consumption, CPU usage, etc. are not at higher-than-normal levels.
(The only way this affects Avant is that, once the freeze occurs, clicking on a tab button to switch to a different tab has no effect on the tab content. The button highlight does move to the clicked tab button, but nothing changes in the rendering pane.)
It's happened so often for so long that I've learned to sense when firefox.exe is about to freeze up. I even created a batch file with a shortcut to it on the desktop that terminates firefox.exe. I frequently execute the batch file as soon as firefox freezes or when the unresponsiveness becomes pronounced enough to interfere with whatever I'm doing
so that I don't have to put up with the frustration of the delayed responses until it finally freezes (I don't do this every time, so I still observe some of the crashes). After I terminate firefox.exe, I just hit Shift+F5 to reload all the tabs. This also prevents firefox.exe from trying to start up in Safe Mode, which is nothing but a big PITA.
This has been happening for over six months in all the various builds of Avant and of firefox.exe that have been released during that period. Whatever is causing it, I hope it can be prevented, because if I can't use the Firefox engine in Avant, I'll have to give up on Avant altogether. The IE and Chrome engines don't even come close to the performance (speed; lack of memory overload) and flexibility of the Firefox engine, and the Firefox engine is the only one of the three that has a full range of extensions available for it.
@ Jasmine: Has Anderson made any progress on this for Avant 2013? Are we still going to see any pre-release builds of 2013 before it actually becomes 2013(the year)?