To Do Exercise #4 bugs

[StuFleisher]

The current solution for question #4 eliminates the delete option for to-dos. It would be helpful to either show an implementation or indicate that students can remove that functionality from their app. I learned a lot trying to get that to work, but it was disappointing to click through to the solution and see that it wasn't addressed.

Also, clicking anywhere in the margins of the list crosses off all to-dos on the list.