QDrawer scrollbars blink infinitely on some resolutions

[zeroinformatique]

Describe the bug
The QDrawer component sometimes make native scrollbar appears (in addition to its own internal, stylized, scroll). On some resolutions or zoom-levels, it will start to blink in-and-out infinitely at 2 FPS.

Codepen/jsFiddle/Codesandbox (required)
You can reproduce this bug on your own documentation website:
https://quasar.dev/vue-components/stepper
The drawers on the left and on the right of the page may trigger this effect.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://quasar.dev/vue-components/stepper
2. Play with CTRL + and CTRL - to zoom-in and zoom-out
3. You may see the native scrollbar pop in for a fraction of a second (this is not normal)
4. Eventually, if you insist at different resolutions and zoom-levels, it will start blinking and never stop

NOTE: On FireFox, I get to step 3 (which is still not normal). On Chrome, I get to step 4.
I suggest testing for this issue on Chromium for easier reproduction.

Expected behavior
The native scrollbar should never appear, especially because this component has its own, stylized, internal scroll.
A workaround is to add the css-class no-scroll on the QDrawer component; it fixed the issue for me.

Screenshots

Platform (please complete the following information):
Quasar Version: 2.0.3
@quasar/app Version: 3.0.3

Quasar mode:

• SPA
• SSR
• PWA
• Electron
• Cordova
• Capacitor
• BEX

OS:
Node: 12.22.4
NPM: 6.14.14
Yarn: 1.22.11
Browsers: Chrome 92, FireFox 90

Additional context
Add any other context about the problem here.

[Evertvdw]

@zeroinformatique I had this same problem but I believe this is happening due to subpixel window heights. I have it for instance on certain heights when using a 4k monitor with 150% zoom (in windows desktop settings). Are you using a zoom at desktop level also?

[hawkeye64]

I also have seen this when using a zoomed of 200% and 125%

Once I removed the zoom, the issue went away. This is indeed a sub-pixel issue with the browsers.

[zeroinformatique]

Are you using a zoom at desktop level also?

@Evertvdw I use 125% DPI for my screens, yes.

[hawkeye64]

I am also curious if this only happens when you have Chrome Dev Tools opened?

[Evertvdw]

@hawkeye64 No, it happens on the PWA installed app om desktop for me too

[rstoenescu]

Fixed it in Quasar v2.4.4 & v1.17.1 (to be released)