imagesc() behaviour with gnuplot and Jhandles

[Michael Grossbach]

Let A be a matrix with values between 0 and 1:
A = rand(128);

imagesc(A) with jhandles as plotting backend shows a 'flat' image with
all pixels set to the same colour whereas imshow(A, []) shows the
expected picture but without the axes. Using gnuplot with imagesc(A)
works as expected. All this under Windows with Octave 3.0.0
Is there a workaround?

Thanks, Michael