Issue with only blue color while resizing the any graph

Hi,

we have been running xymon 4.2.2 from last 2 years on rhel 5.2. Suddenly,
issue of displaying only blue color while resizing any graph is coming
i.e.when we click on magnifier sign on any of the graphs, complete blue
color appears and no graph data is displayed.
Tried to add some code like this in menu.css in www dir,

.zoomSensitiveZone {
opacity:0;
}
.zoomBox {
opacity:0.5;
}

as seen from old posts but does not seem to be working.

Kindly help.