Is anyone familiar with any usability studies for illustration/drawing apps? Most seem to follow a few rough conventions (toolbar on top, layer sidebar on right), but there are definite differences. For example, clicking on a symbol in Keynote immediately inserts the object on the page. On most other apps you have to drag out a size for the object. Powerpoint also allows a single click without dragging to immediately insert the object with a default size, while illustrator opens a dialog asking for an object size. Similar differences between apps in whether or not the current tool remains selected after an object is inserted. I'm curious if anyone has come across a study on the usability of these interactions.