18. The system of claim 15 , wherein the debugger provides an indication that the expression needs to be refreshed if an evaluation error occurred while evaluating the expression.
18. The system of claim 15 , wherein the debugger provides an indication that the expression needs to be refreshed if an evaluation error occurred while evaluating the expression. 19. The system of claim 18 , wherein the indication comprises displaying the expression in grayed out font and displaying a refresh icon adjacent to the expression.