The result of calling NewControlId() must be assigned to wxWindowIDRef to be accounted for correctly, otherwise the id was marked as free while a reference to it still existed resulting in asserts in id management code when we attempted to reuse it. Closes #11604. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65059 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775