<canvas debug="true" proxied="false">
    <view id="tt">
        <handler name="onerror">
            Debug.warn("onerror");
            OUT.setText("onerror");
        </handler>
    </view>
    <button text="trigger resource error" onclick="tt.setResource('http:foo.html')" />
    <text width="100%" id="OUT" />
    <simplelayout/> 
</canvas>
