I'm writing an user documentation for a Web App and I have the following question:
I need to say that the user needs to fill the form in/on the dialog box that will open after clicking a button.
Which one of the following (in/on) is more appropriate when dealing with web objects?
Computer windows, such as the ones that contain dialogs, are metaphoric containers -- notice that you used the term box to refer to it. Therefore, the correct preposition is in. We use on when referring to metaphoric surfaces, so we say that the dialog box appears on the screen.
Perhaps in/on need not be used. Might, "Click the button to open the dialog box and complete the form that appears." work?
