1201217 - Switching tabs in Fennec-APZ sometimes renders the page at an incorrect zoom

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[Kartikaya Gupta (email:[e-mail])]

STR:
1. Start fennec-apz (with the patch from bug 1200399 applied)
2. Load the page http://people.mozilla.com/~kgupta/griddiv.html
3. Open a new tab and load the page http://people.mozilla.com/~kgupta/grid.html
4. Switch back to the first tab

Expected:
Upon switching back to the first tab it looks the same as when we left it after step 2.

Actual:
The page is rendered zoomed out

I looked at the layers dump and after switching back to the first tab in step 4, the layers tree indicates that there is a presShellResolution of 0.5 on the root content document. I used jimdb to stick a breakpoint in nsPresShell::SetResolutionAndScaleTo and found that it was getting set from JS during a Tab:Selected notification, which pointed me to the offending line. Patch coming forthwith.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

Attachment: Patch

I think we might be able to get rid of this line entirely (i.e. even for Java-PZC fennec) but it's safer to just omit it in the APZ case for now and then get rid of it later after we've switched over completely.

For the record I believe this line was obsoleted by bug 732971.

Comment 2

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/137ead96908a

Comment 3

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/137ead96908a