R version 4.0.3 (2020-10-10)
macOS 11.1 (20C69)
This is a recurrent issue. From an Rmarkdown file shown inside the main RStudio window, if you click on
Show in New Window for a plot, the new window shows the plot fine.
But if you first do
Show in New Window with the whole Rmarkdown file, and then click on
Show in New Window for the specific plot within the Rmarkdown file, the new window is empty.