Wanted to drag a folder and accidentally dragged WinSCP's menu somewhere else.
There should not be possible to "rearrange" WinSCP menus just by accident.
I would propose a lock in main menu "View > Allow rearrange menus", default every time unchecked (even when checked in the previous session", checking there to allow next to drag the menus in whatever new positions, then lock it again in View > "Lock rearrange menus"