Created attachment 563786 [details]
Image of Taskbar Preview Issue
Tab content fails to display in taskbar previews
1. In new profile, check option to display previews in Taskbar.
2. Hover mouse over taskbar to display of all tabs open in browser.
Preview of content of each tab will be shown.
See Image attached.
Regression range based on Nightly nightly buids:
Changeset cb4b93331e4f: OK
Changeset b5b082d183d0: Not OK
It's similar for me, but my tab previews are the various tabs' favicons.
In addition it also affects if you have other Firefox windows open. Only if the option is enabled.
Created attachment 563793 [details]
Case with one showing favicon (which was in an individual window) and the missed thumbnail-
Yes, I can reproduce. Looking into it.
I backed out bug 515907 and the problem still persists, plus that bug doesn't really touch the part of the code that generates previews, so I really doubt it's that.
mwu, could your PRBool to bool change have caused this? See <https://hg.mozilla.org/mozilla-central/diff/e7854b4d29ba/widget/src/windows/TaskbarTabPreview.cpp>.
Yep, I'm pretty sure that's the reason.
Created attachment 563827 [details] [diff] [review]
Yep, fallout. We didn't catch this because we were assuming (and not type checking) that PRBool = BOOL.
Ugh, sorry, I always slip up with marking inbound patches as fixed.
I just grabbed the Nightly hourly (C-set ID 164fd1bbd06f) containing the needed patch and can confirm that Win7 Taskbar Previews have been fixed.
Thanks for the fix. Sorry for the initial misdirection. Just think of it as a little test. ;-)
No worries: my patch was the obvious one to blame.