+ AA6YQ comments below
Now that you make me think about it, some months ago I've bought a new DELL Keyboard/Mouse wireless set.
Apart from this i didn't make changes (hardware or software) except changing the mouse color pointer (Mouse Windows preferences) choosing black pointer on white background (I'm an Apple technician since 1984).
After reading your post i restored the default setup (white pointer on white background) and double clicking on a spot now the frequency change! Incredible!
+ I'm glad that the "fix" was simple, Franco.
+ When the behavior of a DXLab application suddenly changes, it's essential to immediately determine what cause that change. If you procrastinate, you may forget information about what changes you made to your hardware and software that may be responsible.
Dave, AA6YQ