UMG Scrollbox animates only after mouse scroll input

Development Programming & Scripting UI
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1

Noticed an odd behavior with the scrollbox in widgets. Even though the scrollbox is set to animate scroll, when manually setting the scrollbox offset in blueprints (using a button), it will snap to the new offset, not sweep (there is no node option to let it sweep). However, if you still allow scroll wheel input and scroll even just once with the mouse, then use a button to set offset in blueprints after mouse wheel input, the scrollbox will now animate to the new offset.

I imagine this is a bug and the scrollbox should either animate 100% of the time from blueprint offset, or not at all.

To replicate:

1.) Create a scrollbox in a widget and fill it with items so it can scroll. (I used a horizontal scrollbox)
2.) Set scrollbox to animate scroll
3.) Create a button that also manually offsets the scrollbox by X amount.
4.) Run it and try the button. It will snap to new offset.
5.) Hover your mouse over scrollbox. Use mousewheel to see animated scrolling.
6.) Try button again, now it will animate to new offset.

2

Bump. I came upon the same issue. Version 4.25.4

3

Hello. Same problem here, exactly. I’m using UE 4. 26.

I have to say, that I tried to put focus on the scrollbox (via blueprint) but it doesn’t work. I don’t know how to fake that wheel rotation via blueprint. Or any patch that works.

Thank you

4

Hey! I’ve got the same issue, I’m using unreal engine 5.2. I’ve investigated editor code and found this line: “const float CurrentViewOffset = bAnimateScroll ? FMath::FInterpTo(ScrollBar->DistanceFromTop(), TargetViewOffset, InDeltaTime, 15.f) : TargetViewOffset;” inside SScrollBox class. So the problem is that this bAnimateScroll is false by default and it turns to true only after mouse wheel input, so if you want to fix it, you probably have to expand the editor code:)

5

Hi, I wonder can you tell to solve with more detail?