Hello Sherman,
You can achieve the desired behavior by using RadSplitter's client-side API.
I suggest to implement a function which gets the height of the dynamic content and after that to call a function which sets this height and is placed on the main page .
I prepared a simple project which demonstrates this behavior - you can find it in the attached archive file. In the sample project there is a RadSplitter with 300px initial height. A content page with a bigger height is loaded in the RadPane and the RadPane is resized to the proper size, so no vertical scrollbar appears.
Feel free to modify the example in order to meet your requirements.
Greetings,
Svetlina
the Telerik team