Question to tutorial 5 about the blocking the interaction

I have a question to the blocking interaction to the first window. I am using ubuntu with eclipse. And when i have the second window and try the click the first one, it is certainly blocked. But when i try click twice so i can get the access to the first one (but i still can't not click the button of the first window or close it). So the blocking don't work anymore.﻿ ???