I would love to change gmail's check mail window not do a window.open, but there are problems that can't be solved with the way the templates are currently designed. One of these problems is that since gmail's templates don't use AJAX for displaying all the contents of the page, doing something like clicking on a folder would result in a new page load and thus losing your check mail status.

I've looked into the popup blocking issue and there shouldn't be one, except for the initial login checkmail popup (if the user has it turned on) due to it being opened on window load. Clicking on a link that results in a window.open() (like the Check Mail link) should be allowed for most (all?) popup blockers - at least it's the case for the google toolbar, ie's built in blocker, and firefox's blocker.

Adrian