Bin colors for TH2 when using COL option

When using the “COL” option to draw a 2D histogram, the empty bins show up as the
color white, even when I extend the color palette axis down to -10. I used these commands
to draw a 2D histogram called “hxy”:

root [1] gStyle->SetPalette(1,0)
root [2] hxy->SetMinimum(-10)
root [3] hxy->Draw(“COLZ”)

and everything looks okay except the empty bins are white instead of the blue color
indicated on the color palette axis at the number 0 (I have attached the plot). How can I fix this?

Yes, empty bins are not drawn with otion col. That’s is how most users want it. At some point we had a version in which the empty bins were painted and we received many complains so we have to came back. I would suggest you to change the background color of your plot in a way it matches the first color of your palette.