Style guide for menu item for modeless dialogs?

[Jon K Hellan <hellan acm org>]

Hi

Is there a style guideline for the following:

What happens to a menu item which launches a modeless dialog,
when the dialog is already up? Assuming that the dialog can only be
launched once, that is.

There are two possibilities:

1. Make the menu item insensitive (grayed out).

2. Let it stay sensitive, and raise the dialog to the top of the stack
   when pressed.

I think I find 2 most useful, but is there an existing guideline?

Regards

Jon Kåre