1374511 - Spurious scrollbars during panel subview transitions

Status: RESOLVED DUPLICATE of bug 940733

(Firefox :: Toolbars and Customization, defect)

Description

[Markus Stange [:mstange]]

Attachment: screen recording

Steps to reproduce:
 1. Open the app panel / hamburger menu.
 2. Switch back and forth between the Web Developer subview and the main panel.

The panel changes its height during the transition between the two views. Sometimes you can see a scrollbar showing up briefly, but it doesn't really look like a scrollbar because it's clipped and because it's only visible for a short moment.
To me, the scrollbar looks like a graphical glitch.

I would recommend one of the following options:
 1. Don't change the panel's size; keep it at the size that's required by the main menu and scrollbars for subviews that require more space. Or:
 2. During the transition, clip the subview in such a way that no scrollbar appears. E.g. <clip><fullSizeReserver><actualContents/></fullSizeReserver></clip>

Comment 1

[Markus Stange [:mstange]]

(In reply to Markus Stange [:mstange] from comment #0)
>  1. Don't change the panel's size; keep it at the size that's required by
> the main menu and scrollbars for subviews that require more space.

This was supposed to say "... and *show* scrollbars for subviews that require more space."
Keeping the panel the same size also gives you a smoother transition, because animating the size of a panel is hard to do in a performant way.

Comment 2

[u428464]

I think this is a dupe of bug 940733.