I have an MVVM view where I am overriding a GridViewDataColumn.CellStylewith a DataTrigger style that changes the colour of the Background based on the cell value (0 is red, >0 is green). This works great, except any cells that have been coloured this way no longer show their horizontal gridlines. The gridlines are still visible on other cells in the same row, and all vertical gridlines are still visible, but no horizontal gridlines on the custom styled cells.
Any idea what would cause the horizontal gridlines not to display just because the Background colour is overridden??
See attached image for an example of the grid with this styling in place.