Plot command fails when followed by a readline()

Question

The following program produces a plot

using Plots
plot(cos)

but this one does not

using Plots
plot(cos)
readline()

I am using Julia 1.2.0 on macOS 10.11.6 with JupyterLab in Firefox 74.0. When encountering the readline() in the latter program it displays a text-entry box which accepts text input but there is never a plot made.

Answer 1

Only the last output is displayed, try

using Plots
display(plot(cos)) 
readline()