`scaleFillManual` doesn't work correctly with numbers

[AndreiKingsley]

If domain of scale is numerical, scaleFillManual works like a continuous scale, even though it should work as discrete:

val yy = listOf(1, 2, 1, 2)
val cc = listOf(1, 2, 3, 4)

letsPlot() + geomTile() {
    x = xx
    y = yy
    fill = cc
} + scaleFillManual(values = listOf("red", "green", "blue", "yellow"), limits = listOf(1, 2, 3, 4))

[AndreiKingsley]

If limits are not specified, it works correctly:

[alshan]

This is expected behavior: scales created for a continuous (numeric) domain are continuous. Try asDiscrete() to annotate the domain as discrete.