STR: 1. Have an old non-boostrapped addon installed in the profile, that also has an options dialog. 2. Use Tools->Addon options->the addon 3. You probably get a new tab with an error that the page couldn't be loaded (or a hang as Jorg observes). 4. If you can close the tab Result: ReferenceError: reference to undefined property "glodaSearchBox" searchBar.js:58:7 TypeError: aOldTab._ext.glodaSearchBox is undefined searchBar.js:58:7 May have something to do with bug 1448939 comment 5. You may have hidden the gloda search box, but some code (from the inlined overlays) is still there that looks for it.

The fix of bug 1448939 comment 5 was that I added a pre-processor define to insert the QFB button and gloda searchfield only in messenger.xul and not messageWindow.xul. From your STR it should only run in messenger.xul and not the standalone window.

There is no standalone window, the Addon options opened in new tab.