Yes, the Zowie EC2-B's sensor is fixed. This means that the sensor will not move and will not track movement until it is reset again. The reason for this is that the sensor is designed to be stationary and is not meant to be moved around or disrupted.
The Zowie EC2-B is an ergonomic mouse that features an innovative Avago ADNS-3090 infrared optical sensor with zero positive or negative acceleration, reducing the risk of accuracy loss from sudden movements. Additionally, it has an adjustable lift-off distance and a CPI range from 400 to 3200 that can be adjusted with the convenient on-the-fly DPI buttons.
I hope this helps!
For more information, you can check out the official Zowie EC2-B product page here: https://www.zowie.com/en/product/ec2-b.html