User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:35.0) Gecko/20100101 Firefox/35.0 Build ID: 20140911064110 Steps to reproduce: 1. Click and drag a tab (should open tab in a new window) 2. Go back to original window and click out of the tab (which should have moved but hasn't) 3. Try to click back into that tab Actual results: The tab will open a new window with a "new tab" opened but will not load the content (it only opens a blank tab in a new window). Then you can close that window and the tab will still be open in the previous window, but once you click into a different tab, you can't click back into it. Clicking X doesn't close the tab either. It's like an image of a tab that has disappeared. Expected results: The tab should have moved from the original window to a new window. It should no longer show in the original window. You should also be able to close out of the tab.

I made a clean profile to test this and realized that this bug only exists with e10s enabled. Without enabling e10s, the tabs work fine.

Can reproduce.

Confirmed 35.0a1 (2014-09-18) Win 7 x64