some further investigation shows that 'TnextDBGrid.VertScrollBarPostion' will not be updated when navigating via 'TdbNavigator'. Therefore 'TnextDBGrid.WMVScroll' results in wrong calls to 'MoveBy'.
I have installed nextcomps_41081.zip, but there is no TDBNextGrid.Rows property! Furthermore the version.pas states "strNextSuiteVer = '4.9.8.1'" and "strNextGridVer = '4.6'", and history.txt: Sep 25 2008 ----------- NextGrid v4.6 Looks like the nextcomps_41081.zip isn't up to date!