Frame in a nestedSplitter window, good idea?

[-Patrick]

I'm trying to create a window/frame/control that is within a 
nestedSplitter window and if maximized should only expand to the size of 
the nestedSplitter. Here's a visual of what's happening, it's created 
OUTSIDE the nestedSplitter.... even though the parent window is the 
nestedSplitter:

http://img401.imageshack.us/my.php?image=firstio8.png

Here's a view of seeing how it should NOT expand:
http://img393.imageshack.us/img393/971/thirdku9.jpg

And finally, aside from setting the size, it should be placed like so 
and not expand beyond the nestedSplitter:
http://img512.imageshack.us/img512/5459/secondwi6.jpg

And here's the code as I've implemented it:
CreateSplitLayout() { 
  mainSplitter = new wxSplitterWindow(this);

  // settings for left window
  leftWindow = new wxScrolledWindow(mainSplitter);
  leftWindow->SetBackgroundColour(*wxBLACK);

  // settings for the righthand side column
  rightWindow = new wxScrolledWindow(mainSplitter);
  rightWindow->SetBackgroundColour(*wxWHITE);

  nestedSplitter = new wxSplitterWindow(mainSplitter);
 
  // settings for the top window
  topLeftWindow = new wxScrolledWindow(nestedSplitter);
  topLeftWindow->SetBackgroundColour(*wxBLACK);
 
  // settings for the bottom window
  bottomLeftWindow = new wxScrolledWindow(nestedSplitter);
  bottomLeftWindow->SetBackgroundColour(*wxBLUE);
 
  mainSplitter->SplitVertically(nestedSplitter, rightWindow, 700);
  mainSplitter->SetSashGravity(1.0);
  mainSplitter->SetMinimumPaneSize(50);
  nestedSplitter->SplitHorizontally(topLeftWindow, bottomLeftWindow, 
550);   
  nestedSplitter->SetSashGravity(1.0);
  nestedSplitter->SetMinimumPaneSize(50);
 
  newFrame = new wxFrame(nestedSplitter, wxID_ANY, _T("Game Window"), 
wxDefaultPosition, wxSize(400, 200));
  newFrame->Centre();
  newFrame->Show(true);
}

Since it's a child of the nestedSplitter.. shouldn't it be placed within 
the nestedSplitter by default? Is there a better way to do what I am 
trying to do? Ie: control instead of a frame, window instead of a frame, 
sizer first.. etc... What am I doing wrong?

Thanks for your time.
-Patrick