Abstract: System and method for debugging a program. A graphical user interface (GUI) displays source code for the program in a first GUI element, and first user input is received to the first GUI element indicating an expression, e.g., including one or more one or more variables, constants, macros, and/or operators, in the source code. A value of the expression is displayed in a tooltip in response to the first user input. Second user input is received to the tooltip modifying the value, thereby specifying a new value, and the expression in the program is set to the new value. The program continues execution in accordance with the new value of the expression. The tooltip includes a first portion, e.g., context sensitive control, displaying the value and to receive the second user input modifying the value, and a second portion, e.g., text indicator, displaying non-editable information related to the expression.