Fix: selection box in scrollable parent container

[deafnv]

Had an issue with selection in a scrollable parent container where the selection wouldn't select following the cursor if the container was being scrolled while selecting, see: https://codesandbox.io/s/staging-silence-q87qdx

Wasn't able to fix it without changing the package so I thought I'd submit a PR, not entirely sure if I'm missing anything here.

Fixed: https://codesandbox.io/s/red-wildflower-hvlwim

[tomaszczura]

Thanks for putting this PR! However, I think this won't work if DragSelection is deeply nested, and it's parent is not actual scrolling element. The element that scrolls should be the same that provides events - configured in eventsElement. I played a bit with codesandbox you provided - I moved DragSelection into elements-container and changed eventsElement to be

eventsElement: document.getElementById("elements-container"),

and now selection comes with cursor when I scroll elements container. You just need to adjust logic for selecting elements.

Please let us know if that solution works for you or you still need some changes

[deafnv]

As I understand it, the issue you mentioned can be fixed without changing my fork? I tried to replicate the issue you mentioned, and the solution does work. Either way, I'm fine with any solution that fixes the main issue.

[tomaszczura]

Correct - I think we don't need any changes to the library, because scroll element is different on different pages - it should be always eventsElement. Let us know if you see any bugs when using proposed solution

[deafnv]

Looks like it works, though it seems like I'm having issues that could be related with #30, but that's a different matter entirely.