I am not sure I have understood properly, but I try to give a possible solution.
If you want to disable navigation with tab (and consequentially with arrow and other keys) you have to set the grid property DisableNavigation to true.
Remember that Enter key moves the cell activation to the next row cell with the same column number. So starting from column #4 it always moves to the next row, independently if a column.
Be careful, if you set DisableNavigation to true, all the native navigation keys handlers of the grid are lost. So you have to re-implement the key event handlers.
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