First off, I read the Questions that may have my answer First.. but still no resolution. Details are that I can't seem to understand why a mesh that I had to separate apart just so I could color the rubberized handle blue, around the chrome handle (which will animate 45 degrees and I have the key ring and tag set to Ridgid Body Physics). I took a screenshot of the Red Handled Lever colored just fine, and the attempted Blue Handled Lever. The main thing I can see with everything I've successfully colored (placed a Material On) is the list of materials at the very top. With the Red (and all other colors that show up successfully) there's just one material in the list, with no toggle up/down window to show the collection of materials. But when I click on the attempted blue one, you can see the list, along with the toggle up/down feature present.
In edit mode select the part of the mesh you want to use a certain material, then select that material from the list and press the Assign button.