Reproducible on 39.0b1 build 2 (Build ID: 20150523155636) Affected platforms: Windows 7 64-bit, Mac OS X 10.9.5, Ubuntu 14.04 64-bit Steps to reproduce: 1. Start a call. 2. Detach conversation by dragging the window. Expected result: Conversation name is displayed. Actual result: Conversation name is not displayed. Notes: 1. Screencast: https://goo.gl/7KZQMx 2. Browser console output when detaching: 'TypeError: win.gBrowser is null' thrown by ReaderParent.jsm:168:0
Created attachment 8659800 [details] [diff] [review] Loop conversation name vanishes if the window is detached by dragging. Don't try to set the title in the wrong place - let the detachChatbox code set the title. I took a quick look at this and it turns out that the drag specific detach code is trying to set the title, but hasn't got the right title. Additionally, the detachChatbox code already has embedded within the facility for setting the title on detach. So I think all we need to do is to remove the broken part of the code.
Verified fixed with latest 43.0a1 (from 2015-09-15), across platforms .  Windows 7 64-bit, Mac OS X 10.9.5 and Ubuntu 12.04 32-bit.