Usually closing that window, or resarting R or RStudio session works, as FJCC said. Since that's not the case with you, I'm going to give 3 suggestions, but please note that these are just guesses on my part.
- Update your
RStudio
. The current version is1.2.1335
, and your version1.0.136
is very old. - Run
dev.off()
a few times, and then try to plot again. - Run
options(device = "RStudioGD")
, and try to plot again.