export_fig does not export impoint, impoly and others

If a plot contains an "impoint" or "impoly", or probably any of these interactive objects from image processing toolbox, the output of "export_fig" simply doesn't show them. The problem happens only when exporting an axes not the whole figure. I would very much appreciate any suggestion?

figure() 
handle = subplot(1,2,1); 
impoly(handle, [1 1; 2 2; 1 2]) 
export_fig('test.pdf', '-pdf', '-transparent', handle)