Question #1 - What is the difference between the icon befor Sketch4 and Sketch5

Question #2 - If I want to change the dimensions of Sketch4, I simply double click on "Sketch4" and it is highlighted and the dimensions become visable.  I can then check them...easy enough.  This doesn't happen when I click on Sketch5.  I am assuming it has something to do with the icon...different type of sketch?  Drawn differently?  I didn't create this file, but now I have to change it.

Thanks!