[TxMt] Output to new window only if non-empty

[Nikolaus Binder]

Does anybody know a way to print the output to a new window ONLY if it  
is non-empty? Perhaps otherwise display a tooltip with a fixed string  
("no errors")?

Background: I am using the cmd-r shortcut to make the project and want  
to display errors - if there are any - in a new window. But in most of  
the cases everything's fine and I have to close that window.

Would be really time-saving if anybody knew a solution.

Cheers,
Nick