Just how it is .. no changing it. The reason some scanners (PSR800,WS1080 etc) are like that .. cause that squelch knob is directly connected to the squelch circuit in the radios.
The other scanners .. are not like that, and you can alternate between volume and squelch. But ... you do not want it any other way than it is, cause .. the squelch is a set it and forget it setting, there is no need to change it.
Set it to the minimum squelch and leave it. I have had my 1095 shortly after they came out, and have never touched my squelch.
I have my squelch about 8 if I recall .. and never change it cause the 1095 has a terrible squelch circuit anyways (ie missing weak signals).
Make the knob the volume and just accept it.