TypeError: aTab.linkedBrowser is null browser.js:6076 when Ctrl-Tab, cannot switch tabs

[mayhemer]

http://hg.mozilla.org/mozilla-central/annotate/5f0569c3cb8f/browser/base/content/browser.js#l6284

Firefox Nightly
extensions:
TreeStyleTab (0.14.2013100100a101917)
Ctrl-Tab (0.21.1)

This happens to me a long time (months), but I didn't get to it to report it sooner.

I have a different Firefox profile where I have only Ctrl-Tab extension installed and I don't have this issue. So I suspect this comes from TreeStyleTab.

Symptoms:
after some time of using a single window with many tabs pressing ctrl-tab stops switching tabs and the error appears in browser console

I so far was not able to discover what triggers the error. New windows work well, reopening the badly behaving window helps too.

[piroor]

I saw similar error message. In my case, ctrlTab._tabList is unexpectedly invalid (it seems having already removed tabs). However, I cannot find out what triggers such a status...

[piroor]

OK, I've found the reason. When you select a parent tab and close the tree, Firefox tries to focus to the first child tab because the current tab (the parent) is going to be closed. However, TST automatically close all child tabs too. As the result, TabWindow.prototype.handleEven (defined in resource:///modules/WindowsPreviewPerTab.jsm) raises an error for TabSelect event on the (closing) first child tab. The error blocks updating tab previews and breaks Ctrl-Tab feature.

[mayhemer]

Testing. However, I think the bug trigger is different for me. We'll see if your fix helps. If not I'll open a new bug.

Thanks for so fast fix!