Didn't find a topic with search and I was wondering if this is under development? Currently I have a 4k monitor and have forced dpi-scaling on both my unity and xfce desktops to 125, and some POL buttons go outside the window boundaries and I cannot resize the windows. Also the texts on main window are still quite small.
We will not fix this for PoL/PoM 4. However, you can switch to Phoenicis PoL/PoM 5 (https://github.com/PhoenicisOrg/POL-POM-5). This allows you to adjust the scaling according your needs. I do not own a 4k monitor, so I couldn't test if everything works as expected. Feel free to open an issue if you find any problems.