Just a thought, under User Preferences on the Display tab have you tried checking the Auto Size Subset or Maximize Group Windows?
I am having the same issue on regular Windows 10 laptops. Not every time HEAT Call Logging is launched, but it will change to super small text in the Call Logging window but the text in the Info Center is fine.
We have tried the adjusting the screen resolution, checked Display settings and changes user preferences. It seems a restart corrects the issue, sometimes.
I entered a support ticket with Frontrange (heatsoftware) regarding the HEAT classic install on Windows 10 displaying very small call log/Asgnmnt/Journal, etc. screens.
The response was "Per Scott, This ticket is being disregarded". ??
I received this information from HEATSoftware in response to my ticket.
Bad news, that is a know issue with the tablets, Surface pros, We have already submitted a RM for the Issue and we are pushing to have this addressed as soon as possible, hopefully for 978 due in November. I will link this ticket to the RM and when the fix is released we will receive notification. There is no know work around at this time.
If I hear anything about a work around I will forward the information along,