riched32.dll or riched20.dll sourcode

Is the sourcecode of riched32.dll or riched20.dll available somewhere

If not - what could I do if i want to create a richedit textfield that behaves slightly different (like changing the control for the scrollbars, such that i can change the size and positions of them from outside)

thanks

From stackoverflow

• In Windows, if one wants to create a common control that behaves differently, they would create it as usual and subclass it.

  genesys : hey! thanks i have already read about sub and super classing. but how would i extend it by subclassing such that i can actually change the logics of the control? let's say i want to be able to display two carets instead of only one. or that the textfield scrolls up if i move the scrollbar upwards (instead of wise versa) how can i do such things?

  GSerg : There can only be one caret, but you can emulate a second caret by hadling WM_PAINT in your subclass routine and drawing that caret on your own. Similarly, you can reverse the scrollbars logic by intercepting WM_VSCROLL and changing it's parameters before calling DefWindowProc.

  Mat : Thanks! Do you know any good tutorials that cover stuff like that?