I remark that matshow are not working with the subplot tool. It's logic because this tools change the aspect of the graph but I remark that you can add the colorbar and that change the aspect too. The problem I have is to have the scale number on the colorbar visible. They are too long on the right and it's diffiult to read them, so I try to use the tool and I nothing move.
Like I told it's probably normal but in this case the colorbar is not consistent with this.