I opened a ticket with the same question - and the support told ME "I can minimize" the window! How great!
I KNOW I CAN MINIMIZE SETUP WIZARD POP UP! - I WANT TO CLOSE IT OR FINISH IT WHILE IM DEALING WITH MY WEBSITE.
HERE IS THE ANSWER OF MY TICKET:
Thank you for opening a ticket today.
Just click the top of the setup wizard, it will minimize itself.
Thank you again for using iClan Websites!