I can somewhat reproduce it, but for me tabs *can* be moved or closed when this happens. The effects for me are: 1. The tab is "stuck" at wherever it was when the download popup has appeared 2. Almost all of the toolbar items are non responsive. The only responsive buttons in that state are the bookmark toolbar ones, the Home button and the Downloads button. All the rest don't respond to hovering, clicking, right clicking etc, but tabbing to them does actually work. 3. When switching to other tabs (or opening new ones), the effects of #2 above are still present. The only way I could find to fix it is to drag one of the tabs over it (or it over others), and then everything gets unstuck. Oh, and restarting the browser also fixes things, of course. Nothing gets logged in the console when this happens. The issue of the tab getting stuck goes *way* back, but I managed to get a regression range only for the issue where the toolbar items get stuck: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=f5d99e9f3d7bf19c8a222db97bedc924da27fd58&tochange=ea7b55d65d76214f97aaae502d65cb26fc6f5659 2017-09-06 to 2017-09-06
Bug 1620094 Comment 6 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
I can somewhat reproduce it, but for me tabs *can* be moved or closed when this happens. The effects for me are: 1. The tab is "stuck" at wherever it was when the download popup has appeared 2. Almost all of the toolbar items are non responsive. The only responsive buttons in that state are the bookmark toolbar ones, the Home button and the Downloads button. All the rest don't respond to hovering, clicking, right clicking etc, but tabbing to them does actually work. 3. When switching to other tabs (or opening new ones), the effects of #2 above are still present. The only way I could find to fix it is to drag one of the tabs over it (or it over others), and then everything gets unstuck. Oh, and restarting the browser also fixes things, of course. Nothing gets logged in the console when this happens. The issue of the tab getting stuck goes *way* back, but I managed to get a regression range only for the issue where the toolbar items get stuck: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=f5d99e9f3d7bf19c8a222db97bedc924da27fd58&tochange=ea7b55d65d76214f97aaae502d65cb26fc6f5659 2017-09-06 to 2017-09-07