Exclamation point in top right of windows - over the close button

Question

When I open some Java applications, especially examples launched from Java Web Start, I will often see an exclamation mark next to/covering the close button, depending on the window size. It is a bit worrying actually.

What does it mean, and what is its function?

Answer 1

It means the app. is sand-boxed. The function of it is to inform the user that an app. is running that is sand-boxed.

See Exploring Security Warning Functionality for more details.

It is supposed to be a bit worrying, actually. Don't go typing your bank account details into one of those floating windows that looks 'something like' your bank log-on. ;)