Out of the box a lot of us Windows users who added all of the Octave-Forge packages are disappointed to find that the plot function produces an invisible window.
Here is the problem and solution:
Realistic solution at this moment, do not install the oct2mat package when you install octave with octave-forge packages if you do not use this package. One one of different solutions is to execute
pkg rebuild -noauto oct2mat
at the octave prompt and then restart octave. The operation results in the oct2mat package not to be auto-loaded in startup. When you want to use oct2mat, execute “pkg load oct2mat” command.