Minimum docked window size

I have a window for which there must be a minimum size, that is, it should not be possible for the user to size the window so that it is less than some specific width.

When using Xtreme Toolkit 1.9.3.1 I had a solution to this (basically, I just simulate the window being resized back to its minimum size by sending the correct messages) but we now have to upgrade to 3.1 and the solution no longer works - the WM_NCLBUTTONDOWN I send to the window's m_pDockBar member causes an assertion in CXTDockBar's splitter array (I think the splitter has been removed from the array by the time I send the message).

Does anyone have any other ideas how I can achieve the same effect, or a solution to the above problem, please?

(This was previously sent by email to Codejock but they haven't replied yet.)

oleg wrote: Use WM_GETMINMAXINFO message:

Sorry Oleg, but that plain just does not work. The window in question never receives such a message. (Note: it is not the main frame window that I am trying to restrict to a certain size, but a CXTDockWindow derived window docked to the main window.)