Shuffling between windows in an active application like Safari - assigning a keyboard shortcut doesn't work!

Hi all!

In Lion I was able to assign a keyboard shortcut to move focus to the next window in an active application, such as Safari or Word. I used a comfortable shortcut cmd+< and it's worked perfectly. Now I just upgraded to Mountain Lion, and I can't assign this shortcut anymore, it simply doesn't work.

Is the command I'm putting wrong? I tried:

Move focus to next window in active application

Move focus to next window

Move focus to active or next window

None of these work. Using Safari is frustrating now, since I have to stick with using tabs in the same window - but I'm used to my way of multitasking which might include many windows with many tabs, and I've been comfortably shuffling between them throughout Lion.

My keyboard is in Finnish languages since the laptop is Finnish, but I'm using English (US) only.

Help is much appreciated! Thanks! 🙂