" I'm not aware of any other development platform in which you can look at the code behind the app with the simple click of a menu "
HTTP-induced myopia strikes again. Not a menu-click, but off the top of my head: Perl*, anything written in shell script, 8-Bit BASICs and Spreadsheets (you don't have to be online to be an application).
I'm sure other people will chip in...
* for Perl, no, that actually is the sourcecode. Yes, someone really did type that.