Chrome Version: 55.0.2883.87 (64-bit)
OS: Goobuntu

What steps will reproduce the problem?
(1) Open 2 windows
(2) On windows 1, hit ctr-s to open a save dialog
(3) Then drag the tab of the window 2, inside the window 1

What is the expected result?
Either the tab is accepted or refused (could be refused since there the window is being blocked by the dialog).

What happens instead?
The tab is kind of accepted (the tab shows up inside the window not correctly) and most of all, my screen is totally blocked. I can't switch to any other apps, until I press escape. After pressing escape everything is back to normal. The computer works correctly, but the screen is forzen.