I've been using the following code:

window.open("", "test",
"height=600,width=480,status=0,toolbar=0,menubar=0,location=0,
resizable=1,scrollbars=1");
myForm.target = "test" ;
myForm.action = "testPage.asp";
myForm.submit() ;


I haven't yet had any problems under IE 5.5(W2K), IE 5.5(SP1-W2K) or IE 5.0.

However, I can't see any real difference between your code and mine! As long
as your "strMnemonic" variable is not empty (or contain "_blank"!) and you
should be fine.

Cheers,
Anil