Can someone help to trigger this VBA function?

[kippiebla]

In an Excel I use a self made function "sumbycolor" to add cells in the same column with 2 different colours (blue and green). It adds nicely, the cells in green seperately from the cells in blue. But when I change a blue cell into green, the sums of blue and green do not automatically adapt themselves to the changed values. It seems that the color change itself does not trigger the sum function to recalculate. Can I do something about this?

[NoSparks]

when I change a blue cell into green

How do you do this, manually, VBA, conditional formatting or ???

Is your sumbycolor UDF volitile ?