ThatGravyBoat

Ive updated the description, the last sentence of the original report already had how to reproduce and what results it expected ands observed but ive made it more explicit

This has been made virtually impossible in 24w33a as the packets were changed to using a tag key id instead of a list of items when it can. So this can probably be considered fixed.

I cant reproduce in 1.21-pre4 so yes it must have been fixed in one of the snapshots for 1.21

I have been able to reproduce this every single time, ive had others also reproduce it, the video I sent was created on a brand new instance with 0 configuration until I started the game.

Like I said in the description use the button not [ctrl]+ [scroll wheel] as ctrl scroll wheel logic will set the list scroll to 0 when its used but the button does not.

@Jiingy it has to be done with the button, not the scroll wheel, as the scroll wheel adds a special call to reset the scroll.

Here is a deobfuscated decompiled version of that special check on scroll from the latest snapshot:

CycleButton<Integer> cycleButton = (CycleButton<Integer>)this.list.findOption(optionInstance);
if (cycleButton != null) {
    optionInstance.set(k);
    cycleButton.setValue(k);
    this.list.setScrollAmount(0.0);
    return true;
}