Minimal example:
library("spatstat.geom")
plot(as.im(Window(demopat)))
Output:
| spatstat.geom 3.4-1 |
spatstat.geom 3.5-0 / 3.7-3 |
 |
 |
Not sure if removing the box was intentional: it was not mentioned in the NEWS and ?plot.im still says
A rectangular box surrounding the image domain is drawn by default; it can be suppressed by setting ‘box=FALSE’
I tried box=TRUE but that seems to add two boxes:

Minimal example:
Output:
Not sure if removing the box was intentional: it was not mentioned in the NEWS and
?plot.imstill saysI tried
box=TRUEbut that seems to add two boxes: