The Whidbey text editor.

It's not just the framework getting a makeover in Whidbey the whole I. D. E. is being upgraded too. Most notably the text editor has some new features. The context coloring system has changed so that now classes are also identified with a bold text. This includes classes that you define yourself. There is also a new method of indicating which part of the file has changed. When you load a file the left hand margin is clear but as you type a yellow area appears in the margin to indicate changes which have not yet been compiled. When you compile these yellow change indicators turn into green ones that show the extent of changes in the file during the current edit session. I found this to be very useful for quickly checking which parts of the file have been modified.