changes to main program re-run the program without clearing the screen first when special functions are defined

Initially I thought it was just an issue with calling `image` in the main function and the defining `mouseClicked`, but after testing different combinations it appears that as long as any special functions are defined, making changes to code in the main program will run those changes but not clear the screen. I've attached a screen shot below. Here's a link to the program: https://www.khanacademy.org/computer-programming/program-doesnt-refresh-with-getimage-and-mousedragged/5970580156448768


Start by reproducing the behavior in the linked Khan Academy program, comparing edits to the main program with and without special functions such as mouseClicked or mouseDragged. Trace the live editor's rerun and screen-clearing entry points; done means main-program changes clear the screen before rerunning even when special functions are defined.

Written by the indexing model from the issue text.