🐛 Variants scrollbar moves by itself. #408

Describe the bug
When you have enough variants so that you have a scrollbar for them, if you drag a variant to move it and drag it up or down enough so that the scrollbar moves automatically for you, when you release the variant, the scrollbar keeps moving indefinitely.

To Reproduce
Steps to reproduce the behavior:

1. Create an Animated Java Blueprint
2. Create enough variants so that a scrollbar appears.
3. Drag a variant without releasing it up or down enough so that the scrollbar starts moving in that direction automatically for you.
4. Release the variant when the scrollbar is still moving (easier to see if you drag and release fast).
5. See how the scrollbar keeps moving indefinitely even if you released the variant.
6. You can only fix this bug by reloading the app.

Expected behavior
Scrollbar should stop moving by itself if you are not dragging any variant.

Desktop (please complete the following information):

• OS: Windows 10
• Version 2009