We could keep using the column previously used for sorting even after UnsetAsSortKey() was called on it. Ensure that this doesn't happen by resetting the owner wxDataViewCtrl sort column index too. Closes #15160. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73834 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775