Scrollbars are hidden when zooming a page

[David.Vincent]

Some users tell me a bug with Noia Fox theme and the new Firefox 32 :

- With CTRL + Mouse weel : go to zoom 120% or 130% for example.
- Scroll the page : scrollbar is hidden

I have tested all main themes for Firefox (Nasa, FT Deep Dark, Lavafox, Wallnut,....) and all themes have the same bug. No problem with FX Chrome because this theme doesn't skin scrollbars.

[therube]

FF 32 Scroll Bar

[patrickjdempsey]

Typically when there is a bug that only appears in a non-default theme that means Mozilla has changed the default theme in some way and the change hasn't been documented or noticed yet. Also, do you use native scrollbars or custom ones?

[Aris]

David refers to custom scrollbars in complete themes. My 'NewScrollbars' add-on is also affected by this new 'bug'.

[Santa_Fe]

Happens when you use NewScrollbars (aka NoiaScrollbars) as well.

[patrickjdempsey]

Hmm... AFAIK there have been painting issues with custom scrollbars since Firefox 4.0 that no-one has been able to properly track-down and fix. For a long time images on custom scrollbars would randomly not load... which made some of them totally disappear. Due to those issues I've basically considered custom scrollbars to be unsupported since Firefox 4.0. Does this issue impact the SeaMonkey Modern theme as well?

[Aris]

That is true, 'missing scrollbar' problems in themes started somewhere around Fx4-7, but Mozilla changed definitively something in Fx32.
Seamonkeys (2.29) modern theme is not affected by this. Maybe we can build custom scrollbars on it?

Offtopic
Just noticed there are no more up to date Aurora and Nightly builds provided for Seamonkey on Windows, while MacOSX and Linux are still getting new builds. Any reason for that?

[Frank Lion]

Seamonkeys (2.29) modern theme is not affected by this.

Yes, it is.

[Aris]

Strange. In my tests I could not reproduce that glitch using a new profile.

[Frank Lion]

Strange. In my tests I could not reproduce that glitch using a new profile.

You did all the zooming about and scrolling? Easy to miss/forget if you're doing lots of dull testing.

This bug is similar to the long standing Print Preview custom scrollbar bug. The first sign is that the scrollbars increase in size as zoom is applied (native ones do not). This latest bug has the added delight that over a certain (variable) zoom level on general webpages that the thumb just vanishes when dragged/scrolled.

@ For those not familiar with messing around with custom/native scrollbars, it should be noted that their coding can be DOMied via the incontent Addons Manager scrollbars.

[Aris]

Same tests as on Fx, but after another SM restart I could reproduce it on SM too.

[patrickjdempsey]

So after manually updating to SeaMonkey 2.29 (what's that about anyway?) and testing with Frank's "Silver Scrollbars" extension, I'm able to reproduce this behavior at zoom levels 50%, 150% and 170% only. Same results with the Modern theme at those zoom levels. Disabling Hardware Acceleration doesn't appear to make any difference.

[therube]

Bug 1066934 - FF32: Skinned scrollbars thumb disappear upon scrolling a page at specific zoom percentage (different between FF themes)

[mcdavis]

According to the bug, fixed for Fx33.

[Aris]

Probably when 33 becomes final this one will be fixed, but currently on beta5 the bug is still present.