When I run the following block of code with alt+Enter:
using Plots
pyplot() # or plotlyjs()
plot(cumsum(randn(1000)))
on a fresh Julia console (freshly opened Juno, or after killing the Julia process), nothing appears in the plot pane. Instead, a big block of text appears in the editor (see attached screenshot).
If the lines above are executed one by one rather than as a block, it works fine. Subsequent plots are also fine. The same behavior occurs with both pyplot and plotlyjs backends.