The gray box painter, responsible for displaying an image, animated GIF, or Java logo before the applet has loaded, is exhibiting flickering during live applet resizes (for example, for applets that are a percentage of the page's width or height). The root cause is the AWT's native painting of the background of this and sub-components; see 6691181.
This is likely related to flickering seen during live resizes of certain applets, although we are deferring the investigation of that flickering in order to incorporate this bug fix first, which contains the necessary utility methods to eliminate said flicker at the applet level.