# Basically https://matplotlib.org/stable/gallery/images_contours_and_fields/matshow.html#sphx-glr-gallery-images-contours-and-fields-matshow-py with a colorbar addedimportmatplotlib.pyplotaspltimportnumpyasnp# a 2D array with linearly increasing values on the diagonala=np.diag(range(15))plt.matshow(a)# this triggers the bug# plt.matshow(a, fignum=None) # this too# plt.matshow(a, fignum=1) # this too# plt.matshow(a, fignum=False) # this triggers the expected outcome# plt.matshow(a, fignum=0) # this tooplt.colorbar()plt.show()