Unwanted animation in sortable list when moving between multiple containers

[vkammerer]

Hello and thank you for the great library,

I noticed unwanted artefacts in my implementation of a dnd between multiple containers of sortable items, which was an adaptation of your <MultipleContainers /> component demoed in the story.

After a while debugging it, I realised the same visual glitch is present in the story itself.
In order to reproduce it, you can:

• go to the story at https://5fc05e08a4a65d0021ae0bf2-fseheekyit.chromatic.com/?path=/story/presets-sortable-multiple-containers--vertical
• drag the first item of the first container (A1) from its position to the bottom of its list (under A5)
• up to that point, all is well: the other items in the list (A2, A3, A4 and A5) have been properly animated to be positioned to their desired position (= at the beginning of the list)
• now keep dragging A1 to the B list: you'll notice that A2, A3, A4 and A5 are animated again from their original position to their desired position

That's for the bug itself. Regarding the functionality's API (dragging items from a list to another): do you think users should implement the low level transferring from one list to another themselves, as visible in the current story, or do you think the library should include an easier solution?

[clauderic]

Hey @vkammerer, sounds like a bug. Could you record a video of the issue to help me visualize it?

[vkammerer]

sure, here it is:

• I drag A1 under A5 and all is correctly animated and positioned
• look at the A column when A1 is drag onto the B list: the A items are animated again (even though they should remain still)

Screen.Recording.2021-01-20.at.2.53.03.PM.mov

[yuri-scarbaci-lenio]

is it a bug tho?
in the video what is happening is that you are resizing the container to fit the new list which has 1 less item then before, as in the list A is not re-animating, it's just re-sizing ?

[reverie]

@yuri-scarbaci-lenio I think the bug isn't that the container resizes, but that A2-A5 "jump" a little when A1 leaves the container. If you remove the last item from a container, and the container shrinks, there should normally be no need to reposition the remaining items.