User Agent Mozilla/5.0 (X11; Linux x86_64; rv:47.0) Gecko/20100101 Firefox/47.0 Build ID 20160222030212 Reproduced on Ubuntu 15.04 x64 and Windows 7 x64. Steps to reproduce: 1. Open Nightly with a new profile and sign in with a Firefox account. 2. Right click on a link and choose "Bookmark this link". -> The New bookmark dialog opens. 3. Click on "Show all the bookmarks folders" down arrow. 4. Click on the "New folder" button several times to create new folders. Expected Result: The "New Folder" button is available for user to create new folders. On every click on the "New Folder" button a new folder is created. Actual Result: After 2-3 clicks on the "New Folder" button the button becomes unavailable (grayed out). This seems to be caused by the fact that the new created folder loses the focus. Note: Seems to work fine if user is not signed in.