When you hover an image/item that you would like to upload into either Google Photos/Drive using the drag and drop method, a blue screen will appear over the window [see attached image] indicating that the files can be dropped and uploaded. However, if you drop the files back into the original location without dropping them into the browser, the blue indication screen won't disappear and you'll have to refresh the entire page to remove it. I can't seem to reproduce this on OSX 10.11.5 but reproduced it many times on Win 10. STR: * login into either Google Photo's or Google Drive * Select a few images/items and drag them over the browser window * you should see a blue indication window similar to the attached image * now drag the files/photos back to their original location without dropping them into the browser * you'll notice that sometimes (90% of the time), the blue message screen won't disappear and you'll need to refresh the page

Michael knows about this sort of thing.

The issue appears to be that dragleave events aren't fired correctly on the document when the item is dragged over XUL UI instead of directly out of the window. The dragleave event seems to only be fired at the last element which the drag is over as it leaves the window. I'll look more into how to get the messages to propagate correctly.

This is the only part I am posting right now for this bug because I have had a very difficult time writing a test for this patch. For some reason I cannot figure out how to get the drag events to be fired correctly in an automated test environment. I have been trying to drag an <img> tag from content over chrome, and see if dragleave is fired the right number of times, but I can't get any drag events to fire :'( I would love some hints as to how I could implement a test for this bug. I have tested it manually and it seems to work correctly. This is a regression which only occurs on e10s firefox when the file is dragged over chrome on its way out of the window. The document never receives its dragleave event, which means that the "drop files anywhere to upload" screen never disappears. This patch fixes it by correctly propagating the event to content.

Is this the same as bug 1256952? The patch there is much simpler if so.

(In reply to Neil Deakin from comment #4) > Is this the same as bug 1256952? The patch there is much simpler if so. I just tested with your patch from bug 1256952 and yes, it seems like your much simpler patch solves this problem. Marking this bug as duplicate.