That's it. You found the influencing root cause. I selected a compromise of icon size and scale based on my screen resolution (3840 x 2160, medium icons and 200 %). Thank you so much.
Anyway, may I ask you for a favor:
It's a compromise, and I am quite glad that it is working at least. But I am 50 years old wearing decrepit caused glasses . I personally think that machines should be adopted to humans, not vice versa. With my new laptop, resolution changed from 1920 x 1080 to 3840 x 2160 while the monitor attached to the docking station is still 1920 x 1080. I am used to "my regular sized icons and font size". I would like to have 250 % as before. 250 % is also the recommended size. This size is meaningful as a doubling the resolution from 1920 x 1080 to 3840 x 2160 results in a factor 4 x smaller icons. This would be compensated by exactly 250 %.
Therefore, I do not like the compromise and, honestly, as Fences is a desktop solution I expect it to work with different icon types and scales. Can you please report this to Fences development so solve / compensate in Version 4, please?
Thank you so much for your work and all effort you put on my to help me find a solution.