Design Layers & Sheet Layer should be change to just Layers & Sheets. The reasoning is because 1st, Sheet Layers are have nothing to due with Layers. Sheets are a singe presentation or a final presentation sheet that are not layered on top of each other. 2nd Design Layers should also be rename as just Layers. The resulting change in the names would be one syllable words that are easy to underdstand and less confusing; We would end up with "Classes, Layers & Sheets" very distinguishable names. I have found that using 2 syllables and using the word Layers twice confuses people when I am trying to explain the difference "Design Layers & Sheet Layers." Now the word "Design" is a general word that could be use on all three categories example: "Design Classes, Design Layers & Design Sheets." But then again we are going back to using 2 syllable names for a description. So I hope some day I will see a change of the names that will show up as "Classes, Layers & Sheets."