I found a bit of a solution if you accidentally click on the arrows and it moves the window to a place that it shouldn’t be and you cant get it back.
Go to ACF and create a NEW field group and create one field inside (doesnt matter what we are going to delete it, we just need something on the page), place it on the page/post/template where you are having the issue and then go back to the page/post and you should be able to move the item back to its original position. Then go back to ACF and delete the field group you created earlier.
Hope this helps.
