Color issue with URDF and multiple visual tags

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I am trying to build a URDF model that comprises different components with different colors. However, I don't necessarily want every component to be its own link; I'm just aiming for a higher level of visual fidelity. I saw here that it's possible to have multiple <visual> tags within a given <link>:

http://answers.ros.org/question/10913...

...and indeed, this works. However, subsequent <visual> tags appear to have their <material> tags ignored, and instead get painted the color of the first <visual> tag. In other words, if I do this:

  <link name="link1">
    <visual>
      <geometry>
        <cylinder length="4" radius="1"/>
      </geometry>
      <material name="black_metal">
        <color rgba="0.1 0.1 0.1 1"/>
      </material>
    </visual>
    <visual>
      <geometry>
        <cylinder length="2" radius="5"/>
      </geometry>
      <material name="gold">
        <color rgba="1 0.549 0 1"/>
      </material>
    </visual>
  </link>

...then BOTH my cylinders end up getting colored as the "black_metal" material. Is this a bug, or am I simply using URDF in a manner which was not intended?

EDIT: I'm using Hydro.