After advancing to Act IV I noticed my shield slot was disabled. I'm using the same one-handed sword I used in Act III. I thought maybe I had removed a ring or something and my stats had lowered making me unable to use the shield but my stats are plenty high.
Has anyone else had this problem or is this by design. I guess I can sell my one-handed with weapon skills and go to a two-handed sword but I'd rather have a choice in the matter.