Dialog Modal Option Causes lag

Dialog Modal Option Causes lag


When i set the modal option for my dialog to true it cause the browser
(FF3) to lag after pressing close or any of the input buttons. If I
remove the modal it works perfectly. It also shoots FF3 memory
consumption to over 300MB
This is my code for the dialog:
    $("#statusInfo").dialog({ //Defines status dialog
        autoOpen: false,
        modal: true,
        width: "800",
        height: "600",
        title: "Status Info"
    });
I ideas to want might be causing this?
Thanks