When you start dragging the issue, the target (place where you're about to drop the card) should have the placeholder for the issue (greyed out container with the same height).
We do not show the original issue until it's dropped. Functionally, adding a class to it (dragged) and moving it around to the target to use it as the placeholder would be enough actually.
When you drop the issue, it should be instantaneous rather than taking a few seconds for the issue to be moved column. You display it where it is and silently in the background save/sync. If it fails, you move the issue back and add a class to it (like failed), we'll make it pop out to communicate the state back to the user.
While you're saving/syncing the state, we can have a small loader/animation in the top section (class='controls')
We need to replicate what trello does:
failed
), we'll make it pop out to communicate the state back to the user.class='controls'
)