**BUG** Concise problem statement: The displayed measurement of difference in frequency (dx) between two cursor points is incorrect Steps to reproduce bug: 1. Run a frequency measurement test, say between 10Hz and 100Hz 2. Place the cursor at say 10Hz on the response line and click and drag very slightly to measure to as close as possible to the originally selected point. 3. View the "dx" measurement Results: Nowhere near zero! Expected results: Close to zero 4 Place the cursor at say 10Hz on the response line and click and drag left until the dx measurement falls to zero. Results: The measured difference between cursor points is zero Hz Expected results: The measured difference should only be zero when the cursor points are coincident. NOTE ALSO THAT THE DEFINED START AND STOP FREQUENCIES FOR A SWEEP ARE NOT COINCIDENT WITH THE X AXIS FREQUENCY CALIBRATIONS. Browser: Opera and Internet Explorer Windows 8.1