674487 - During tab drag, after pressing alt+tab, window no longer receives all mouse events, sometimes resulting in stuck panel

Status: RESOLVED INVALID

(Firefox :: Tabbed Browser, defect)

Description

[Frank Yan (:fryn)]

During tab drag, after pressing alt+tab, the window containing the dragged tab no longer receives mouse events outside itself and its panel, sometimes resulting in a stuck panel, if mouse leaves the panel too quickly and if mouse button is released in that state.

Comment 1

[Frank Yan (:fryn)]

Oddly enough, this is Windows-specific.

Comment 2

[Frank Yan (:fryn)]

Dão, the only sane way I can think of to fix this without creating a hidden widget and/or creating event loops is to use the drag&drop API, but I haven't been able to close the performance gap, which I consider to be a higher priority than anything else for this feature. If you think you can or want to try, you're welcome to own moving the implementation to the drag&drop API.

Comment 3

[Dão Gottwald [:dao]]

I'd be happy to look into it if I had a useful starting point. I'm not eager to implement the drag & drop API use from scratch when I'm unaware of the steps taken when and after it was ripped out. I could try to unearth these steps by studying the patch history in bug 455694, but I'd rather not do that either. I'm afraid this would be time-consuming and unenjoyable archeology for someone who didn't author these patches.

Comment 4

[Frank Yan (:fryn)]

(In reply to comment #3)

I will put together a mostly working patch (on top of the patch for bug 533460) that makes tab dragging use the drag&drop API again, with which you and/or Neil could investigate any performance problems or glitches. Give me a few days.

Comment 5

[alex_mayorga]

STR:
Open two (2) Nightly windows
"Tear" a tab from Nightly window 1
Without releasing the mouse button, Alt+Tab to Nightly window 2
Try dropping the "torn" tab on Nightly window 2 tab strip

BUG:
If you move the cursor upwards fast enough, it detaches itself from the "torn" tab that is left floating around.

I see this on today's Nightly and I believe I started noticing first on yesterday's Nightly.

Am I experiencing this same bug or a variant of it?

Comment 6

[AndreiD[QA]]

> Am I experiencing this same bug or a variant of it?
As noted in the Description, if using alt+tab while detaching and dragging a tab out of the tab strip, results in a stuck panel. There may different visual results, but they all reflect the same issue. I am attaching one of my result using alt+tab while detaching a tab

Comment 7

[AndreiD[QA]]

Attachment: detached_tab_stuck

Comment 8

[Frank Yan (:fryn)]

Patch in bug 455694 was backed out.