Reproducible on the latest Nightly (BuildID: 20140731030206): Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:34.0) Gecko/20100101 Firefox/34.0 Mozilla/5.0 (X11; Linux i686; rv:34.0) Gecko/20100101 Firefox/34.0 Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:34.0) Gecko/20100101 Firefox/34.0 Steps to reproduce: 1. Start Firefox. 2. Open new window; 3. Open Eyedropper tool from the Developer submenu; 4. Try to use the Eyedropper tool on the other opened window. Expected results: Either the mouse cursor or the Eyedropper tool is visible on the second window. Actual results: The mouse cursor is not visible while moving it on the second opened window. Notes: 1. This issue is not a regression: it reproduces since the Eyedropper feature has landed in bug 939040.