Missing focused indication for shaded box
There is currently no way to visually identify a focused shaded box. Box remains black. Find a way to see that a shaded box is selected. For non-shaded box, it is identified with the background color which doesn't work here.
As far as I can see GNOME Crosswords Editor has the same issue. Qxw has an arrow in the background for both shaded and non-shaded cells.