Scrollbar jumps in settings when clicking a button after scrolling way down

[grorp]

Luanti version

Luanti 5.12.0-dev-18ac8b20f (Linux)
Using LuaJIT 2.1.1703358377
Built by GCC 13.3
Running on Linux/6.8.0 x86_64
BUILD_TYPE=RelWithDebInfo
RUN_IN_PLACE=1
USE_CURL=1
USE_GETTEXT=1
USE_SOUND=1
STATIC_SHAREDIR="."
STATIC_LOCALEDIR="locale"

Operating system and version

Ubuntu 24.04.2 LTS apparently???

Summary

The scrollbar in the settings menu jumps when clicking a "Set" button in the "Advanced" -> "Advanced" section after scrolling way down.

scrollbar.jump.mp4

This is a regression from #14623 / 13f533d: fixed if I revert that commit (revert still applies cleanly on latest "master" branch as of today :o)

(I noticed this a while ago but didn't get around to opening an issue until now)

CC @SmallJoker

Steps to reproduce

1. go to settings
2. check "show advanced" checkbox
3. go to "Advanced" -> "Advanced" category
4. scroll way down
5. press "Set" on any setting
6. observe the scrollbar jumping

[Desour]

I guess what is happening here is that the default scroll value from the scrollbar[] element is clamped, and the maximum is updated later (i.e. >1000), after parsing the elements.

A simple fix for just this case would be to make the max value larger via scrollbaroptions, just so that the value isn't clamped.

Should we maybe store the default scroll value when parsing scrollbars, and set it later?