User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b10) Gecko/20100101 Firefox/4.0b10 Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b10) Gecko/20100101 Firefox/4.0b10 When you try to put a placemark (blue icon) on a custom map, the placemkark icon doesn't follow your mouse (it stays on top left corner of the map) and you cannot place it on desired place. This issue doesn't happened on FF 3.6 (I cannot try again because I uninstalled that version) and IE8. On FF4b8 and b9, when you click "Add a placemark" button and you move your mouse, map moves to top continually. This doesn't happen on b10. Reproducible: Always Steps to Reproduce: 1.go to maps.google.com 2.Sign in 3.Click on "My Maps" option 4.Create a New Map 5.Click on "Edit" button 6.Click on "Add a Placemark" (blue icon) on map top left corner. 7.Move your mouse on map to put placemark. Actual Results: Placemark icon stays still on map top left corner. You cannot move it to desired place. Mouse icon disappears on map (you can see it on menus and regions other that map). Expected Results: Mouse icon changes to placemark icon (blue icon) and it follows your mouse through map to a desired place. When you click on it, placemark is positioned on desired place. HP Pavilion 2016LA laptop (ATI Radeon Mobility 4200).