Windows 7 not lowering volume of other sounds when receiving calls through Shoretell Communicator

This may be a simple question but I can't figure it out. At my work I use the Shoretel Communicator to place and receive calls. I like listening to music in between calls so it would be really nice if I was able to get the feature to work where the volume of other sounds is turned down by 80% during call.

At control panel > sound > communication, I have selected to lower the volume of other sounds by 80% when windows detects a communication device being used, however whenever I receive a call everything stays the exact same volume.

Any Ideas?

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