Ok, I get it: there is a (quite well hidden) bug in the wizard’s last page (the plug-ins selection one).
Actually, the WIP checkbox is grayed because of the sample selection (a plug-in is automatically selected when a sample requiring it is used on the previous page). But the checkbox click handler is bugged, and disables the selection (without visual feedback) when it is grayed
If you don’t click on the checkbox, you don’t have the bug anymore…
Actually, you don’t even need to go to the last page (since the plug-in is in fact selected thanks to the sample selection), and click Finish on the sample selection page will also work.
For information, the wizard has been redesigned in 1.1.2, and this bug won’t exist anymore.