This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
My wild-assed guess would be that having two modal dialogs/windows displayed from the same parent browser would hang because the two dialogs would be stuck fighting over which got the focus. Is there a way to turn off the modality of the first window when displaying the second?