389659 - Scrollbar dragging broken when using fullZoom != 1.0

Status: RESOLVED FIXED

Description

[Sylvain Pasche]

Steps to Reproduce:
1. Change the fullZoom on a page, so that you can see horizontal/vertical scrollbars. I used "getBrowser().markupDocumentViewer.fullZoom = 2" in the JavaScript Shell.
2. Try to scroll horizontally/vertically by dragging the scrollbar
3. See how the scrollbar does not follow the mouse movements.

I could reproduce this on Windows and Linux, so that should be a rather cross-platform issue.

Comment 1

[Steffen Wilberg]

It does kind of work, but you have to drag further until something happens. If you grab the vertical scrollbar and move it to the bottom, nothing happens at first. But as you drag further to the bottom, the page starts scrolling.

By the way, I use this in Firefox's error console:
top.window.opener.getBrowser().markupDocumentViewer.fullZoom = 2;

Comment 2

[Eli Friedman]

Created attachment 274065 [details] [diff] [review]
Patch

I'm not sure where exactly that math was messing up, but I don't really care.

Comment 3

[Eli Friedman]

Please don't add checkin-needed to my bugs... the reason I haven't checked this in is that the tree is closed.

Comment 4

[Eli Friedman]

Comment on attachment 274065 [details] [diff] [review]
Patch

Patch makes scrollbars use standard utility method to calculate coordinates; unlikely to cause regressions.

Comment 5

[David Baron :dbaron: ⌚️UTC-7]

Comment on attachment 274065 [details] [diff] [review]
Patch

a19=dbaron

Comment 6

[Eli Friedman]

Checked in.