Derived control doesn't work in collapsed group

To suit my needs for a control on the Ribbon, I derived a new class from it:

class ValueEditRibbon: public CXTPControlEdit{
public:
...
protected:
  BOOL OnHookKeyDown(UINT nChar, LPARAM lParam);
private:
...
};

I use the OnHookKeyDown to make sure only certain patterns can be entered (numerical values with fractions).

I put it on the ribbon like this:
ValueEditRibbon* veValue(new ValueEditRibbon());
pGroup->Add(veValue, ID_EDITABLE_VALUE);

This all works fine.

When I make the application screen small, the group with this control collapses. This is intended behavior of course.
However, when I click the arrow down to unfold it, the edit box is there, but its OnHookKeyDown is no longer called. The control seems to be cast down to a CControlEditRibbon.



What can I do to make it work?

Thanks,

David.