User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:39.0) Gecko/20100101 Firefox/39.0 Build ID: 20150630154324 Steps to reproduce: 1. Open Firefox in safe mode. 2. Open a new tab. 3. Drag & drop this tab inside Firefox (to open it in a new window). Actual results: The new window appears completely off-screen. It is not possible to use it at all. I need to quit Firefox and restart it. For instance, the geometry of this new window (as output by the xwininfo utility with the id obtained from the window list given by the FvwmWinList module of my window manager Fvwm): 2093x1773+3568+520 on a 3200x1800 screen. Expected results: The new Firefox window should appear within the screen limits. Note: if I use the "New Window" function from the Firefox menu, there's no such problem because my Fvwm configuration lets me position the window if there isn't enough room (ActivePlacement feature).
This might be related to tabbed browsing or something ??