White bg in Spearman cor diagonal?

[sami10007]

Code

library("psych")
library("corrplot")   

M <- mtcars 
M.cor <- cor(M)

p.mat.all <- psych::corr.test(M.cor, adjust = "none", ci = F)
alpha <- 0.05
col <- colorRampPalette(c("#BB4444", "#EE9988", "#FFFFFF", "#77AADD", "#4477AA"))  

lapply(
  c("r","p","t"),
  function(ID) { # http://stackoverflow.com/a/40531043/54964
    x <- p.mat.all[[ID]]    
      corrplot( M.cor, 
                p.mat = x, 
                sig.level = alpha, 
                insig = "blank", 
      ) 
  })

Output: spearman r diagonal is white, please see the linked thread for the figure

R: 3.3.1
OS: Debian 8.5
Related: http://stackoverflow.com/q/40533069/54964