[Freebytes]

The Apply button was pointless. OK is supposed to apply. Apply simply made the changes, but it did not dismiss the dialog. Apply seemed confusing to most users and there should have only been two buttons. If you click OK, there was no reason to keep the dialog visible since you should be able to click the same thing (easily) to get back to it.

If the Apply button was necessary because you could not easily get back to the dialog, then it was a problem with the interface before the dialog opened. That is, it should be easy to open dialogs, close them, and open them again.