visual studio does keep a tab on your "active" horizontal cursor position so on the second down arrow it seeks there if it can, just checking rich edit control docs for a flag to see if windows users might have the option but no idea sry, it's kind of like a justify option but not really, and wouldn't be practical unless you were using a fixedsys font i think.
http://msdn2.microsoft.com/en-us/library/ms651894.aspx
http://msdn2.microsoft.com/en-us/library/ms651894.aspx