IBInspectable properties stopped showing

I marked three properties as IBInspectable and they worked great. Later, I decided that three more properties I used would benefit from IBInspectable as well, so I marked them as well.

After tagging a new set, the three previous three have disappeared from Interface Builder. Of the new three, only one of them appears.

I've tried deleting and recreating properties, waving new ones, hoping the old ones will reappear, delete and recreate my own view in Interface Builder, force all views to refresh, close and reopen Xcode, and so far nothing has helped to get them back.

Are there any other tricks I could try running again?