1 of the 5 plots are missing in the graphic

Question

I want to plot all ROC curves in one graphic with the plot function, but the first plot (tree.perf in blue) is separate from the others.

Can someone help me out with this? Thank you in advance

# ROC curve all models
# decision tree 1 pruned
plot(tree.perf, col='Blue', lwd= 2, main= "ROC curves")
# decision tree 2 pruned
plot(tree.perf2, col='Yellow', lwd= 2, main= "ROC curves")
# glm
plot(glm.perf, add=TRUE, col='Green', lwd= 2, main= "ROC curves")
# glm2
plot(glm.perf2, add=TRUE, col='Orange',lwd= 2, main= "ROC curves")
# glm3
plot(glm.perf3, add=TRUE, col='Purple',lwd= 2, main= "ROC curves")
abline(0, 1, untf = FALSE, col = "gray60", lty = 2)
legend('bottomright',legend=c('decision tree1','decision tree2','glm1','glm2','glm3'), lwd=3,
       col=c('Blue','Yellow','Green','Orange','Red'),bty='n')