how to resolve a problem in catia?

hello everyone
i want to know what`s the problem when you make a sketch totally with dimensional and geometric constraints [the outline is in green ] and then when i go to function the message shown is that i can`t make any function the message is
" The sketch is not totally constrained (under constraint). Define the required constraints (click on the change option) or
deselect the "Generate update errors when sketch is under constraint" option available through Tools> Options> Sketcher to prevent the application from generating update errors."