Idea Summary
Enable developers to declaratively remove dialog close button (upper rigth corner) and disable dislog close on Esc key press.

Use Case
When user has to close a dialog by pressing a regular page button, instead by just hitting Esc or the default close button.

Sometimes additional actions need to be run when closing the dialog, but Esc/default dialog close events cannot be caught easily. 

Preferred Solution (Optional)
Provide two additional switches for modal dialog pages: Show close button, Enable close on Esc key