Drag & Copy from one pane to another

[beethoven]

Just upgraded from Win 7 to Win 10 and noticed that all of a sudden I seem to be unable to copy files between different folders when just dragging them from one pane to the second pane. It seems I need to use right click now and then copy and paste which seems a lot more clumsy. Am I doing anything wrong or is there a setting I need to adjust or is this a Win 10 problem?

[beethoven]

Well, seems whatever caused the issue has gone away. Copy function works as usual again