Slide 21
In order to understand how it was calculated, the programmer has clicked on the result 6 (as with a URL, it is underlined and when the mouse moves over it, the cursor changes to a hand). Now we can see the code that calculated the factorial of 3, but with the variable x replaced by its value of 3. These values are shown in blue to distinguish them from the code; mousing over them pops up a tooltip containing the variable name. The code in gray (here simply the number 1), was not executed by the program. It is still shown for consistency with the original source code, but with lower saturation to allow the programmer to concentrate on the executed pieces of code. Note that fact is underlined. We can click on it to see its execution.