See above description, no file is ever selected during that process, here it is again:
- start WinSCP
- start a session with a sftp-site which has many dirs
- click random dirs within tree panel
- most of the time the Fx-Options are grey
- sometimes they get selectable and then above is possible/happens
Believe me, I'm not able to reproduce that. The "sometimes" does not help.
What about this: You visit child directory. The you move back to parent directory. In that case WinSCP automatically sets focus on the child directory in file list. You cannot see that before focus is on the tree. Then the Fx are enabled. You would see the focus if you click Tab while in tree. Normally the ".." will get focused. In this case, it will be the "child" directory.