When I open the sign-off  box on the upper right hand corner (under my name),  both 'Available' and 'Invisible' items are in light color and not operable. How can I make it operable? I believe my problem is right there because my other computer work fine with 'Available' in dark color and marked.  How can I fix my problem?

When I open the sign-off  box on the upper right hand corner (under my name),  both 'Available' and 'Invisible' items are in light color and not operable. How can I make it operable? I believe my problem is right there because my other computer work fine with 'Available' in dark color and marked.  How can I fix my problem?