When doing $(...your selector here...).is(\":hover\"), jQuery prior to 1.9.1 gave correct answer, while jQuery 1.9.1 tells you this:
$(...your selector here...).is(\":hover\")
Erro
Assuming your selector is #myid, use $('#myid:hover') instead of using .is().
#myid
$('#myid:hover')
.is()
If you are using $(this) or a variable, use myVar.filter(':hover').
$(this)
myVar.filter(':hover')