The focus behavior is annoying and now that you’ve shown it I cannot unsee it.
But it’s not different to editor losing focus when a button or JSON tab is clicked.
A fix isn’t impossible but won’t be clean - remember if editor is focused when drag starts, store that value somewhere, focus back when drag finishes.
It’s a wontfix issue until after the redesign.
Explorer is overall very experimental, so also a wontfix for now.