This should be very easy:
An option not to focus into newly opened window but stay in the current one instead.

Can this function be instantly hacked with a macro:

$OnOpenTab = handler;

handler{
# what here to tranfer the focus back?
}

Hmm. Maybe I could do something like this:

injectJS( "onload=function{self.opener.focus();}" )

This, however is extremely crude. A real browser support would be appropriate.

Are you referer to Open Tab in Background?
When you open in background current tab have focus.

There are an event named 'OnOpenWindow'.

I don't understand you like say?

K-Meleon in Spanish