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开发者_开发问答 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

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