Force User to Close Form with Button

[customaware]

I have a form that MUST open in a TAB or Default as a PopUp does not allow the display of Edit button in the reference table on the form.

Even using Default, it opens in a new TAB.

That would be OK except that there is then the option for the user to close the form by closing the Tab rather than clicking the Save or Close button.

Is there any way to disallowing closer this way? Need user to ONLY be able to close by clicking the Save or Close button.