Not happening here (Vista 64-bit system). Also, it's not 'strange' that you get the same problem in both Poser 7 and PoserPro as the code base for the posing room is almost identical.

I don't think this is SM's problem. Could your system be using a mildly exotic mouse driver? If so, try updating. If it's a default driver, also try updating it.

---

Windows 10 x64 Pro - Intel Xeon E5450 @ 3.00GHz (x2)

PoserPro 11 - Units: Metres

Adobe CC 2017