Firefox 49 crashes when unhiding Tab Tree in certain conditions

[dkasak]

Firefox 49 crashes for me with the latest Tab Tree in AMO if:

1. Tab Tree's position setting is set to Left.
2. There are more tabs than can be displayed on the screen at once so Tab Tree's scrollbar appears.
3. Tab Tree is hidden (by pressing F8, by default) and then unhidden (by pressing F8 again).

Tab Tree then freezes very shortly (for about a second) and then the browser crashes.

I've tried stepping the addon in Firefox's JS debugger and it appears to crash after stepping into this line.

I've managed to reproduce this on a clean profile with only Tab Tree installed and I'm on Arch Linux.

[dgaletic]

I have the same bug with Firefox 49 on Linux Mint 17.3. It doesn't seem to depend on the number of tabs that were open prior to hiding Tab Tree, as it: a) didn't crash if I closed excessive tabs while Tab Tree was hidden, and b) crashed if I opened additional tabs while it was hidden (enough to invoke the scroll bar).

[Fabiensk]

Concerning the bug #176 : my video card is an AMD A8-7600 processor with an integrated Radeon R7.

[traxium]

Couldn't confirm on FF 49.0.2 Mint 18 VMware. What's your video card manufacturer, Intel? Line aDOMWindow.document.documentElement.removeAttribute("tt-auto-hide-when-maximized"); triggers these CSS rules from tt-auto-hide.css:

#main-window[sizemode="maximized"][tt-auto-hide-when-maximized] #tt-toggler {
    visibility: visible;
}

#main-window[sizemode="maximized"][tt-auto-hide-when-maximized] #tt-sidebar,
#main-window[sizemode="maximized"][tt-auto-hide-when-maximized] #tt-splitter {
    visibility: collapse;
}

Most likely Firefox crashes when #tt-sidebar becomes visible. Try adding and unchecking visibility: collapse to #tt-sidebar. If Firefox crashes try display: none instead:

[Fabiensk]

Thanks for your help. I have done the test you suggest (still with Firefox 49.0.2):

• before maximizing the video, I put the attribute "visibility: collapse"
• maximize
• press "escape" to leave the full-screen
• disable "visibility: collapse" => no crash
• do it again without modifying "visibility" => crash

I have absolutely no idea of the kind of fix necessary. I personally can live with it and wait for Firefox 51.