iDraw Opacity

I often use iDraw for simple mechanical illustrations, using multiple layers. When selecting an individual component on a layer, the opacity tool located in "Appearance" drop-down is helpful. Mind you, I am not referring to the opacity tool for an entire layer but rather for an individual component on a given layer. My problem is that the damn opacity tool keeps disappearing under the "Appearance" tab. See my screen shot for clarification. So far, my only workaround is to close out of iDraw and open a new document, effectively restoring defaults. I have not been able to address the issue otherwise. Someone please help!