The reason why "Wear" is greyed out is because you are wearing a locked RestrainedLove attachment. "Wear" may accidentally kick such attachments, thus why it is disabled as soon one attachment gets locked, with the exception of objects containing the name of their attachment point in their name (for example, if you got a collar named "My Collar (spine)", you may still "Wear" it as long as no locked attachment is worn on your avatar's spine).
The Cool VL Viewer however implements an auto-reattach feature for locked attachments, and if you don't care about possible failures to auto-reattach when SL is experiencing asset server issues, then you may re-enable "Wear", via the "Advanced" --> "RestrainedLove" --> "Allow Wear" toggle (if the Advanced menu doesn't show in the menu bar, press ALT CTRL D to enable it).
Note however that the scripter of a RestrainedLove object may decide to make the latter issue a @defaultwear=n command, in which case, "Wear" is disabled again (see the RestrainedLove API specifications
Please see also this post
about "Add to outfit" and "Replace outfit".