Thanks for your suggestion.
We will see, if more people ask for this.

Hello,

it is already possible to simply paste the text /etc into the remote tab and WinSCP will go to that directory. However, when you paste a string with a filename like /etc/fstab, this leads to an error message "Error listing directory".

/etc/fstab is then shown as an empty directory, and when you go up one level, fstab is the active/selected file.

WinSCP should check if the pasted string is a directory or a file and either open the directory (as before), or open the parent path and select the file.