One of my biggest UI wishes is that material and component selection in the viewport would be directly reflected in the corresponding panels. currently the way to select a similar material or component to the selected one in the component or material lists is more than awkward, involving several steps.
in case of selecting an existing material applied to a geometry:
1. select attributes panel in pick
2. click on the material icon
3. a list will pop up and the material editor too. the material is selected now - but you cannot use it yet.
4. if you hit just OK, the used material is DESELECTED again and selection will revert to active material in the materials palette. if you hit cancel, the same. I don't see the logic of this, probably a bug.
5. instead, you have to scroll through the materials palette list, manually select the same material as indicated in the attributes panel.
a simple click in attributes/parameters should directly select it in the palettes. or even better implement a hot key which selects materials directly - without the need to go through the attributes tab - when clicking on any part of the scene.
(Originally suggested by 3dworks)