521954 - Moving mouse over a Windows 7 taskbar tab preview causes browser window to flicker and titlebar to change shape.

Status: RESOLVED DUPLICATE of bug 526693

(Firefox :: Shell Integration, defect)

Description

[[not reading bugmail]]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.3a1pre) Gecko/20091012 Minefield/3.7a1pre (.NET CLR 3.5.30729)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.3a1pre) Gecko/20091012 Minefield/3.7a1pre (.NET CLR 3.5.30729)

Browser window flickers and titlebar changes shape when hovering over a aeropeek preview.

Maybe aeropeek is also causing focus and selecting a tab even when your only hovered over the current tab which is hightlighted.  This happens on every tab preview.

Reproducible: Always

Steps to Reproduce:
1. Open browser
2. Insert New tab
3. Select taskbar tab preview
Actual Results:  
Watch browser window titlebar change size and shape and browser window flickers

Expected Results:  
titlebar doesn't change shape, browser doesn't flicker.

In comparison, IE8 just changes its glass color of its navigation bar on hovering over a tab preview and doesn't flicker the entire browser.

Comment 1

[[not reading bugmail]]

This affects both the trunk and 1.9.2 branch.

Comment 2

[Gary [:streetwolf52]]

Same thing for me.  In addition the tab strip turns black with my theme that 'glasses' the tab strip

Comment 3

[Rob Arnold [:robarnold]]

If by flicker you mean it shows the window 'as-is' without the tab you're trying to hover, then we can't do anything about it. IE8 has the same problem for its content area. We have the problem for our chrome area because we redraw the chrome (which IE8 does not).

Can you clarify what you mean by the titlebar changing shape? Do you mean the glow behind the text?

As for the resizing, is this the same as bug 520807? If not, please provide some better steps to reproduce because I cannot.

Comment 4

[[not reading bugmail]]

Flicker meaning the whole browser repaints when you move from the taskbar to the previews but not between tab previews.  I'm not so much concerned so much about the glow with FF, as IE8 just appears to glow its navigation bar not border glass.  But how can we minimize the maximized preview jolt users see.
Which I hadn't even tried previews under non maximized windows for comparison.

Bug 508207 was not clear to me what the issue was.. For awhile, I thought the odd glass box on the preview was the issue there and couldn't reproduce that.  

Now that you mention it, maybe this is what they are trying to say about bug 508207: When running maximized windows, moving from the taskbar to the preview modifies the shape of the browser window or its borders.  The titlebar to me just looks like it moves up and off the screen (resize, newly shaped titlebar) when you move to a preview from the taskbar.  As shown in the screenshot of bug 508207, the rest of my browser doesn't appear to change size, but its like it inserts space at the of top and moves to from (0,0)<->(x,y) to (x,-y)<->(x,y).

Comment 5

[[not reading bugmail]]

Sorry for the spam, that should be bug 520807, hmm.

Comment 6

[mbr]

Here the same problem.

Title bar without select the tab window in the aeropeek: http://www.izipik.com/fr/images.php?date=200910/31&img=hr8pi8mue8nil3l18g-bug3.png

There no problem of course.

Now with mouse cursor on the selected tab window in aeropeek: http://www.izipik.com/fr/images.php?date=200910/31&img=ldp03zmvr7cgm1nqoi-bug4.png

Comment 7

[Rob Arnold [:robarnold]]

There are two separate issues here: the titlebar issue appears to be bug 520807. The flicker issue is unavoidable - even Notepad exhibits it. I'm inclined to call it an OS bug and one that we cannot fix.

Comment 8

[Mike Beltzner [:beltzner, not reading bugmail]]

--> RESO INVALID as per comment 7 if this is an OS issue?

Comment 9

[u88484]

I was just about to file a bug and it may have been a dupe of this one so I'll ask here.

I see a flicker whenever the close button is drawn and removed from the preview.  I guess the window is repainted each time the close button is shown/removed from the preview.  Is this the same thing that is being talked about here?

Comment 10

[u88484]

Ok, playing around some more and I came to the conclusion this is the same bug.  Here is STR:

1) Have tabs opened and middle tab focused
2) Hover over the Minefield taskbar icon to get the previews
3) Hover the mouse over the middle preview

When the close button is drawn, the entire chrome and content area get repainted, favicon in the title bar disappears, product name disappears, minimize/restore/close button shrink

Move mouse back to the Minefield taskbar icon and everything returns to normal.  Keeps moving mouse back and forth as much as you please to see the bug over and over again.

Comment 11

[u88484]

Attachment: Screenshot

Hmm, the minimize/restore/maximize buttons didn't shrink there because they are already smaller in the non-maximized state.  Also, the glow still shows for the bigger buttons when the bug occurs.

Comment 12

[Rob Arnold [:robarnold]]

Yeah, that's not something we can fix or work around.

Comment 13

[u88484]

I have to disagree Rob (not that I know the code) but I truly believe some of this is a Firefox bug.

Active Tabs:
Using IE8 (64bit), when I hover over the active tab, nothing flickers except the title bar glow changing a little and sometimes the min/restore/max buttons color changes and the glass somewhat loses its color.  

Using Trunk, when I hover over the active tab, the title bar does kind of the same thing but the chrome and page content both get repainted, the favicon as well as the product name go missing. This does not happen with IE8.

Now this does happen with both:

Inactive Tabs:
Using IE8 (64bit) and Trunk, when I hover over the active tab and then onto an incative tab, the chrome and page content get repainted.  But this only happens once per taskbar preview.  This is probably what you are refering to as being the same as with IE and probably an OS bug...although I don't see this behavior with notepad or paint.

Comment 14

[Rob Arnold [:robarnold]]

(In reply to comment #13)
> Active Tabs:
> Using IE8 (64bit), when I hover over the active tab, nothing flickers except
> the title bar glow changing a little and sometimes the min/restore/max buttons
> color changes and the glass somewhat loses its color.  

The titlebar flickering may or may not be unavoidable (see bug 520807)

> Using Trunk, when I hover over the active tab, the title bar does kind of the
> same thing but the chrome and page content both get repainted, the favicon as
> well as the product name go missing. This does not happen with IE8.

IE8 doesn't change it's chrome area at all, hence no flicker there. This is not counting the titlebar since that's handled specially - if you look carefully, the glow for the title for the active tab is always present. Also if you look carefully, they do have titlebar flicker (again, explained in bug 520807). They do repaint their content.

re: the favicon disappearing - I can't repro this with or without the workaround in 520807 so please file a separate bug on this.

re: the product name disappearing - this is the .title property of the nsITaskbarTabPreview object that you're seeing during the preview. We control this. File a separate bug on this (not sure if I think it should be fixed or not - that's for someone else to decide).

This leaves the flicker of the content and chrome. Now for tab previews (which only IE8 has), the parent window of the tab is not hidden. What we draw is an overlay for that window. During the time that we are drawing the frame, there is the infamous spinning circle placeholder (bug 522262) - is this what you're seeing?

> Now this does happen with both:
> 
> Inactive Tabs:
> Using IE8 (64bit) and Trunk, when I hover over the active tab and then onto an
> incative tab, the chrome and page content get repainted.  But this only happens
> once per taskbar preview.  This is probably what you are refering to as being
> the same as with IE and probably an OS bug...although I don't see this behavior
> with notepad or paint.

I gave these STR to Joe on IRC - I probably should have posted them here earlier.

STR for notepad/paint:
Open two notepad windows of the same size and overlap them (overlapping not strickly necessary but it makes it clear what's happening). Now preview between the two. Despite the invariant that your mouse is always over a preview, there is a brief moment in the transition where neither window is visible and you can only see your desktop.

STR for IE8:
Open 3 tabs of different content (I used google/the new tab page/msn.com). Select the 3rd tab. Preview between the first two and you'll briefly see the third as you transition.

Comment 15

[u88484]

(In reply to comment #14)
> re: the favicon disappearing - I can't repro this with or without the
> workaround in 520807 so please file a separate bug on this.
> 
Filed bug 527103

> re: the product name disappearing - this is the .title property of the
> nsITaskbarTabPreview object that you're seeing during the preview. We control
> this. File a separate bug on this (not sure if I think it should be fixed or
> not - that's for someone else to decide).
> 
Filed bug 527105

Comment 16

[u88484]

(In reply to comment #14)
> This leaves the flicker of the content and chrome. Now for tab previews (which
> only IE8 has), the parent window of the tab is not hidden. What we draw is an
> overlay for that window. During the time that we are drawing the frame, there
> is the infamous spinning circle placeholder (bug 522262) - is this what you're
> seeing?

No, although I do get that all of the time.  What I am seeing is the entire title bar, chrome and content flicker when mousing over different tab previews.  After I have previewed each of the tabs, I do not get a flicker when hovering over any of the tabs.  I then get a nice fade in/out when hovering over different previews.  The first time a preview is hovered over, everything in the window flickers and does not smoothly fade in/out.

Comment 17

[u88484]

I know changing previews does a fade in/out transition which is fine but in my  STR is always see the content from the first tab fading in/out in every tab.  Maybe this is only happening due to there being no content drawing in my second tab (since it is blank) so Firefox is drawing whatever the last content was while doing the transition?

Comment 18

[Rob Arnold [:robarnold]]

(In reply to comment #17)
> I know changing previews does a fade in/out transition which is fine but in my 
> STR is always see the content from the first tab fading in/out in every tab. 
> Maybe this is only happening due to there being no content drawing in my second
> tab (since it is blank) so Firefox is drawing whatever the last content was
> while doing the transition?

Is it always the first tab or is it the currently "permanently" selected (i.e. the one that's selected when not doing the preview) tab? If the former, that's a bug. If the latter, then we can't fix that - it's an OS bug as in comment 7.

Comment 19

[u88484]

(In reply to comment #18)
> (In reply to comment #17)
> > I know changing previews does a fade in/out transition which is fine but in my 
> > STR is always see the content from the first tab fading in/out in every tab. 
> > Maybe this is only happening due to there being no content drawing in my second
> > tab (since it is blank) so Firefox is drawing whatever the last content was
> > while doing the transition?
> 
> Is it always the first tab or is it the currently "permanently" selected (i.e.
> the one that's selected when not doing the preview) tab? If the former, that's
> a bug. If the latter, then we can't fix that - it's an OS bug as in comment 7.

Whatever the currently selected tab is when the previews are opened.  I think we resolved this as INVALID (OS Bug) in bug 526693 though.

Comment 20

[Rob Arnold [:robarnold]]

(In reply to comment #19)
> (In reply to comment #18)
> > (In reply to comment #17)
> > > I know changing previews does a fade in/out transition which is fine but in my 
> > > STR is always see the content from the first tab fading in/out in every tab. 
> > > Maybe this is only happening due to there being no content drawing in my second
> > > tab (since it is blank) so Firefox is drawing whatever the last content was
> > > while doing the transition?
> > 
> > Is it always the first tab or is it the currently "permanently" selected (i.e.
> > the one that's selected when not doing the preview) tab? If the former, that's
> > a bug. If the latter, then we can't fix that - it's an OS bug as in comment 7.
> 
> Whatever the currently selected tab is when the previews are opened.  I think
> we resolved this as INVALID (OS Bug) in bug 526693 though.

Yeah, this looks like the same bug then.

Comment 21

[[not reading bugmail]]

I was thinking that the whole flicker thing might be happening because the aero peek preview is being cached after you hover over it, not before.  Once you mouse over the preview and it gets displayed, hoving over those previews again become smoother.  I wonder if that would be able to be fixed?

Comment 22

[Rob Arnold [:robarnold]]

(In reply to comment #21)
> I was thinking that the whole flicker thing might be happening because the aero
> peek preview is being cached after you hover over it, not before.  Once you
> mouse over the preview and it gets displayed, hoving over those previews again
> become smoother.  I wonder if that would be able to be fixed?

The flicker happens because Windows doesn't have a bitmap of the live preview when it wants to display it. We are currently lazy about providing one, waiting until it's requested to compute it. We could be eager but I'm not sure if that would have an adverse effect on performance. We would have to figure out when it was a good time to compute it and I don't think we have that information.