Press <Shift> <Left Mouse> on the uppermost list entry
Do as above to mark all, and afterwards press <Shift><Left Mouse> on the mail # 10. The uppermost 10 mails are now marked.
Hold down the <CTRL> key and select the mails you like to select. Note: WebCit will display every mail you select.
Note: These operations work for marked mails.
Change the menu bar to Room view (if you didn't already) Hold down the <Left Mouse> on the mail(s) you want to move, Drag them over to the folder you want to move to, release the mouse key
Move them as above or just press the <Del> key
Its not nice, but its there:
Advanced -> Create a new room
and now enter: