156547 - collapsed scrollbars should not trigger reflow

Status: NEW

(Core :: Layout, defect, P3)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Right now collapsed scrollbars trigger reflows, which is wasteful.  See bug
156522 comment 4, and the testcase on bug 156522.

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: patch, v 2.0

This patch actually works without the one from bug 156522.

Comment 2

[David Hyatt]

Comment on attachment 90678 [details] [diff] [review]
patch, v 2.0

sr=hyatt

Comment 3

[Brian Ryner (not reading)]

Comment on attachment 90678 [details] [diff] [review]
patch, v 2.0

r=bryner

Comment 4

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

I checked in the XBL changes, 2002-08-06 06:39 PDT, but I didn't check in the
nsGfxScrollFrame.cpp change because I noticed a problem that it causes when I
maximize a window showing (scrolled a bit from the top) a page that needs a
scrollbar at the small window size but not the large one.

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: remaining part of previous patch

Comment 6

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

The problem with this patch still remains.

Comment 7

[Boris Zbarsky [:bzbarsky]]

Is this still relevant after roc's recent checkin?

Comment 8

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

I need to check...

Comment 9

[Michael Haufe]

Possibly related to Bug 451816?

Comment 10

[Boris Zbarsky [:bzbarsky]]

Not related to that, no.

Comment 11

[[not reading bugmail]]

FWIW, I noticed recently while playing with performance tweaks on on Windows Vista/7 and visiting other bugs about reflow being triggered (the one with the test to count the # of reflow triggers).  

If the Windows setting to turn off 'show contents of window while drag' is unchecked, it reduces the reflow to 'one time' if just resizing the browser window then let go.  But, it reflows 'continuously' while resizing the window with the Windows setting enabled.

So currently it appears that Firefox gives users this instantaneous effect that where we see the size/layout of the all browser content in order to adjust to maximum viewing pleasure.

Comment 12

[Sylvestre Ledru [:Sylvestre]]

Moving to p3 because no activity for at least 1 year(s).
See https://github.com/mozilla/bug-handling/blob/master/policy/triage-bugzilla.md#how-do-you-triage for more information

Comment 13

[Sylvestre Ledru [:Sylvestre]]

Moving to p3 because no activity for at least 1 year(s).
See https://github.com/mozilla/bug-handling/blob/master/policy/triage-bugzilla.md#how-do-you-triage for more information