i have a 4k 42" display and i have to say, the design is bad in renoise. The fonts and symbols are very small and i didn´t see any scene that makes it possible to show it bigger. You can’t resize or reorganize the frames, so there are big empty areas that are totally useless… please make it possible to zoom… at least like it´s in Browsers, where you can zoom in and out with CTRl and mousewheel. Surely it would be better, if you let choose a symbol and font size and simply make the different frames like effects or instrumentview more flexible and resizable. You could make an option to keep windows like sampler or plugin opened and not to be switched. I think today 4k uses more and more people, so you can´t ignore that and surely it offers many oppurtinities for a better worklflow on one screen !
More and more users complain about this.If you read in these forums, you will see that it has already been discussed repeatedly.
You can lighten the sight a little (up the fonts):https://forum.renoise.com/t/any-way-to-change-the-size-of-fonts/46948