The Tabs dialog scrollbar disappears after entering/exiting Select mode

[Softvision-GeluHaiduc]

[Affected Versions]:

• Firefox Reality version 8 RC1 (7a444d0)

[Affected Platforms]:

• Oculus Quest - Android 7.1.1
• HTC Vive Focus Plus - Android 7.1.2

[Prerequisites]:

• The Firefox Reality browser is opened.
• Make sure to have 14 tabs created.

[Steps to reproduce]:

1. Click the "View Tabs" button in the menu tray.
2. Click the "Select" button in the tab dialog.
3. Observe the scrollbar.

[Expected results]:

• The scrollbar remains displayed after entering Select mode in the Tabs dialog.

[Actual results]:

• The scrollbar disappears after entering Select mode in the Tabs dialog.

[Notes]:

• After a tab is hovered the scrollbar reappears.
• As a side effect after the Tabs view is scrolled the scrollbar resizes, but only on the HTC device.
• The issue is also reproducible on exiting Select mode.
• Attached a screen recording of the issue here.

[bluemarvin]

Scroll bars on android are difficult. I think we need to re-evaluate our usage and implementation of them.

[Softvision-GeluHaiduc]

I have verified that this issue is no longer reproducible with the latest Firefox Reality version 10-40720037 (dbb8ed3) installed on the Oculus Go, Quest, HTC Vive Focus, HTC Vive Focus Plus and Pico Neo2 headsets.
Now, the Tabs dialog scrollbar doesn’t disappear after entering/exiting Select mode.