Status bar shows page loading completion before it takes a place

[marss]

When loading the page, which performs continiously the server-side
work, the status bar shows the progress of the loading process. If page
contains the element, changing its "background-image" property while
mouse move over it, the status bar shows that the page load is
complete,
namely you can see that the "Done" appears in left bottom corner and
the blue strip reflecting the progress hides. But the page is not
loaded yet. How can I resolve this problem? I can't remove all
"background-image" properties from style-sheet, because after that the
site I work with looks much worse.

Here you can see entire example of this problem:
http://64.78.15.74/test/Test.aspx

Еxample explanation: Click top link that cause postback to server.
While page is loading move mouse over bottom link and status bar will
show page loading completion.
Bug only in IE6, firefox works correctly.

I got this bug in 2 cases:
1. When apply style for link in css:
a:hover
{
background-image: url(some.gif);
}

2.When change link appearance by javascript:
... onmouseover='this.backgroundImage=some.gif' ..