after working on ArcGIS Viewer for Flex the map image got out of focus

Hi, I have noticed that after working with some operation on the map service..like zoom, click, search, layer definition, the map is out of focus...like there is another layer over the map.. If I trace the network, I can get the url called to get the image from the ArcGIS Server...and if I run the link in another window of the browser I see that is pretty clear....the same image inside the viewer is totally out of focus...why??
Someone knows the problem?
Thanks in advance,

Naty