Insight
Insight is a version of GNU Project Debugger that uses Tcl/Tk to implement a graphical user inter-face. It is a fully integrated GUI, not a separate front-end program. The interface consists of several separate windows, which use standard elements like buttons, scrollbars, entry boxes and such to create a fairly easy to use interface. Each window has a distinct content and purpose, and can be enabled or disabled individually. The windows contain things like the current source file, a disassembly of the current function, text commands (for things that aren't accessible via a button), and so forth.
