When using Render path OpenGL 2.0, the shadows cast by Saturn's rings cannot be turned off.
When the "Render" "View Options" menu "Ring Shadows" box is not checked, and when using the OGL2 render path, the rings cast shadows onto the planet, although the planet does not cast shadows onto the rings.
When the "Render" "View Options" menu "Ring Shadows" box is checked, both types of shadows are cast.
When any other Render path is selected which can draw ring shadows, the checkbox controls both types of shadows.
This problem is seen with both 1.4.0pre6 and the version built from the most recent CVS code.
System:
256MB 500MHz P3, WinXP Pro, SP2
128MB 250MHz FX5700LE, ForceWare v66.93
Celestia v1.4.0pre6 & CVS