There is a general issue with Windows on 4K monitors.

You mean that the cursor goes extremely small right? => That's a Windows 4K monitor issue. I have this most of the time, NOT always, but most of the time in multiple apps including Poser and Blender.

On a 4K monitor, my personal Poser UI setting is 1.5 in General preferences :=> Interface => UI Scale => Interface Scale factor => Set to 1.5 Restart Poser.