638427 - Inactive windows sometimes paint on top of Firefox

Status: UNCONFIRMED

(Firefox :: General, defect)

Description

[Dan Weiss]

User-Agent:       Mozilla/5.0 (Windows NT 5.1; rv:2.0b12) Gecko/20100101 Firefox/4.0b12
Build Identifier: Mozilla/5.0 (Windows NT 5.1; rv:2.0b12) Gecko/20100101 Firefox/4.0b12

This problem happens intermittently, but I've seen it happen at least 5 times by now.
Here's the situation.  I'm running Firefox maximized.  I have another program running.  I click off that program and click onto Firefox.  As expected, the program's window is deactivated, goes behind Firefox, and Firefox's window moves to the front.  But sometimes, several seconds after this happens, the other window will paint its contents inside of Firefox.
I've seen it happen with at least two different programs, so Firefox has to be the culprit here.

Reproducible: Sometimes




I have the menu button and tab bar integrated into the title bar, if that matters.

Comment 1

[Jim Mathies [:jimm]]

Would you mind posting your about:support data?

Comment 2

[Tim (fmdeveloper)]

Reporter -> Are you still experiencing this issue? Have you tried safe mode or a new profile?

Comment 3

[Tom]

I have been getting the same (or a similar) thing. It started in Firefox 4.0 but is still there in 7.0a1. It often happens with animated portions of the background window, for instance the seekbar in my mediaplayer, or the animation in ClamWin during a scan - I don't see the entire background window, just a small portion.

I'll try a clean profile, but it's very intermittent so it might take a while to reproduce. Once it's there though, it doesn't disappear by itself, but it will go if I mouse over the affected area or scroll the Firefox window.

I'll upload my about:support data. I have a rather **** integrated graphics chip, but the drivers are up to date.

Comment 4

[Tom]

Attachment: about:support info

Comment 5

[Tim (fmdeveloper)]

Did you try running in safe more or with a clean profile for a while? Were you able to reproduce it then?

Comment 6

[Dan Weiss]

I've seen it happen several times in the past week, but using Firefox with a clean profile in safe mode is out of the question, I'm not giving up my Noscript and Adblock just to confirm a bug.  But I have seen the problem happen on two different user profiles, I've seen it happen in Nightly, Aurora, and Beta.
I really don't see how any extension could cause problems with another program drawing on top of Firefox.

What I can tell is that the background program is drawing stuff, and Firefox isn't covering it up correctly, which suggests a problem with clipping rectangles, or overlapping windows.  Since the background program draws on top of Firefox, it has gotten a device context, has requested a clipping rectangle, and has done its drawing.  So somewhere along the line, Firefox didn't properly tell Windows which areas are part of its display, so the application behind Firefox doing the drawing gets a bad clipping rectangle, and draws over Firefox.

This bug has been in here since Firefox 4.  I suspect that it is related to how the maximized window without a title bar operates.