Internal data must be always initialized whether the source object contains choices data or not. This is the backport of r78484. See #16855. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@78515 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775