In both my Nightly profile and my local build profile the toolbox tab order keeps getting lost. I always want the inspector in the first or second position but it keeps moving to the right for some unknown reason. It doesn't seem to reset which panes are visible, just the order. After the reset: devtools.toolbox.tabsOrder = webconsole,jsdebugger,memory,inspector,styleeditor,performance,netmonitor,storage,accessibility,https-everywhere-eff@eff.org I have the https-everywhere extension so maybe the way that gets added is causing problems? I don't have STR as a regular restart doesn't cause the problem. This started in the last 3 weeks I think.

Thank you for the reporting. I'll take a look this.

Are you using the browser content toolbox? If yes, it's most likely this: https://bugzilla.mozilla.org/show_bug.cgi?id=1469075

Yes, I use it almost every day. Thanks.

Fixed in 64 in bug 1469075.