Using the latest stable current production release of Chimera, 1.2304, I have begun to experience some drawing problems that I never had in previous versions. Specifically I frequently get a thin wireframe rendering of my protein structure when I draw the structure as a ribbon with a volume open at the same time. This wire frame persists even when I turn the display of the molecule off in the model panel, and it also does not rotate or translate if the protein is selected as the only active object. In effect it leaves behind a ghost image. Curiously this representation alternates from a light gray/white color to black when I open dialog boxes. The artifact toggles on and off with the volume in some instances. My processing and graphics hardware have not changed recently, nor has operating system (Linux). I do not experience this behavior with my last version of Chimera, 1.2199; it never renders this artifact. I have a nVidia Geforce 6800GT graphics card with the nVidia Linux drivers 1.0-9746. My X11 server is version 6.8.2. Here is a screen image of this phenomenon http://msg.ucsf.edu:8100/~baucom/images/chimera_image.jpg I have rotate the model slightly to show that the thin wireframe stays behind. It is not a separate object in the model panel. Thanks Albion