Just tested Windows 1.4.9 and found 4K screen support has stopped working as it did in 1.4.8. The scene when logged in is fuzzy and I am guessing at around 720p? The start-up screen is also probably a clue. I had to shrink screenshot as 'too large to upload' at 144 dpi so reduced to 72 dpi.
Go to the Edit menu and set a screen size. (you can type in the scene size manually)
When I use retina resolution in the vmware virtual machine I have to select double size to get a normal size viewer.
Note that for the startup screen, the web-view will not scale to the edges over a certain resolution.
OK I'll try that. Weird that in previous version it just worked and I changed nothing, even start-up screen was full screen.
Wow, you run in a VM! VMware Fusion or Parallels? I use VMWare, in fact, I have my full Mojave startup disk now in a VM in case Catalina fails on something I need. That was a fun ride thanks to Catalina's new APFS setup.
OK UPDATE: Edit/ size was already correct at Ultra 4K yet low res continues.
OK UPDATE: Edit/ size was already correct at Ultra 4K yet low res continues. I tried setting to 2560 x 1440 and starting and then quitting and resetting to 3840 x 2160 in case it was sticking, but no luck, Still low rez on entering inworld.