Graphs not rendering in PDF when using dev.new() with knitr

[Higgs32584]

Hi, so recently, I was using knitr to compile graphs for my homework and, I was adding dev.new() before all of my graphs, as I thought this was the normal format to create graphs in. What did end up happening though, is that graphs that followed dev.new() did not render at all in the pdf. while I understand dev.new is a function in the graphics package, I ran into no issues when compiling the graphs in markdown, as they all displayed perfectly fine, the code interaction seems to be related specifically towards how knitr compiles .rmd into a .pdf.

A warning label related to instances of dev.new() in the compilation would be ideal, as I imagine taking into account new graph windows might be too complex.

library("robustbase")
data("coleman",package="robustbase")

dev.new()
barplot(salaryP ~ fatherWc,data=coleman)

dev.new()
plot(salaryP ~ fatherWc,data=coleman)