Awhile back with Platinum numerous users including myself had 4K resolution issues. I lost all of the transport buttons plus everything to the right of them. They were there but nothing could be clicked. The only fix was to keep the % of your viewing area to 100% which is impossible to see on a 43 inch monitor.

Looking OK here with 250% om Win 10 1803
 
...but so is Sonar Platinum 23.10.0 build 24 2017 10

I doubt its the 4k. Sounds more like your video card/drivers may be up to no good.

Ok I installed it and the transport isnt working and the timeline zoom function is wacky. Everything looks like its working for the most part. My video card drivers are all good, I had no issues on my older 1080p tv but when I upgraded the monitor Sonar is the only program that freaked out. Very odd. The Sonar devs said it was because I was using a "tv" and not an actual computer monitor. I thought that was an odd response.

Could be the TV. Could be the brand of TV. Maybe Sonar doesn't like the display adapter. Only way to know for sure is to try it on a 4k non-TV Monitor. My 17" Alienware 4K laptop screen displays everything as it should in Sonar & CbB.
 
FWIW, I don't use full 4K because it's no good for apps on small or medium monitors. It's designed for games more than anything else.

Yea its just a bummer.  Ive had these problems since the change and I use the TV for a lot of 4K stuff.  With the size it makes it a lot easier to navigate too.  Ive tried a few other DAWS (Studio One, Reaper) and don't experience the problems Ive just used Sonar for almost 10 years so I'm so used to it. 

I had upgraded monitors a while back.  I friggin cheaped out and bought an off brand 1080p like an idiot and now I have to use a custom screen resolution in order to view the entire screen.  It works fine now, but sometimes an update resets and I have to figure out how to adjust it again.  This isn't just Cakewalk, it starts at my desktop.  Anyway, just wanted to point out that sometimes it could be the monitor.

This should work, I have used it for other applications.
http://pocketnow.com/2016/01/25/hidpi-scalling-in-windows-10
 
Consists of one registry value and a text file that  is put in the same location as the exe file.

43" 4K LG TV here @ 125%. No issues after upgrading my VC to support it. The only reason I use 125 is that some unscalable application text is just too small.

I do not have 4k myself, but several people I was helping have them. And no one has complained something does not work, I also could "click" transport remotely without problems. With Platinum and CbB.