Problem with use "Register" or "Login" on the "tools" area

let's say i want to register. i click on the register button and a window pops up. when i am trying to write something in any of the boxes (name, username, email etc) the pop up window disappear !

same with login.

Any help ?

That's weird.
Probably some interference with some 3th party extension classes or script.
We need to see it to check what's wrong.