MonoDevelop red text

Hello! I’m new here and I can’t solve this problem.

       When I'm typing sometimes text is red. My friends don't have this problem and now I don't know what I can do. I was looking for answer in the other pages but every solutions aren't working for me.

      Please tell me if you know how to solve that because I have some Unity lessons in school and this annoy me very much. 

      That's not an error because my game works very well.

hey @TezzyXin ,I don’t know how to fix it But, I think you have to try that: open monodevelop
Double click on Assembly…(all of them on the right) > Build > General >change Target framework to anther version of .Net framework (I am not sure this is would work But i hope it Would).