Before I found the shortcut keys, this was really getting on my nerves, so I just thought I'd mention it here. I'm aware the run button runs the last active layout, but I routinely just wanted the whole project to run (which I know F4 does, but at the time I didn't). At first when I kept getting a blank black screen and I was confused as to what was going on. I later realize the run was for layouts. I kept having to re-select the first layout (after editing others) in order to run the project, and having to scroll the project list to find the layout and open it in order to run it was too much. At the time I was right-clicking the project root node to run the project, but I have to scroll up the projects panel to the top to do it. I was losing my hair. ;) I had figured that since the help tips never mentioned a shortcut that there wasn't one, but later on I found it.
C2 really needs something like what Visual Studio has for web design: You select an active project (bolds the name), then you select a "startup" page. It doesn't matter what you are editing - when you select "run", it runs the active project, and launches the startup page (or "layout" in C2's case).
C2 needs two buttons for new comers: Run Layout (as is), and Run Project. At the very least, put the shortcut references in the help tips! ;)
Jack of all trades, and master of some.