I'm having the same problem. I run RM7 under Windows 10 Professional on a desktop machine and on a Lenovo Thinkpad with a 14" screen. On the Lenovo, the six generation pedigree window has impossibly minute type; five generations show up as expected. I've installed the latest Intel graphics drivers and the registry patch mentioned above to no avail. My font sizes and displays for all other programs are perfect.
The RM7 program_options/display settings show that all three fonts are set to Segoe UI (14 point); this font's smallest setting is 8-point, but the names in the six-generation pedigree window are about 1/3 the height of 8-point Segoe. Times New Roman shows the same result. The shapes of the characters appear to be controllable in RM7, the the size -- at least on the six-generation pedigree chart is not.
I do not think this is a Windows 10 problem as RM7 is the only program which manifests it. I think there may be something wrong with the scaling algorithm and I would very much like to learn of any progress in solving the problem.