My VO was set to run in a window, and it starts in a window of the expected size, but the game screen is much bigger. I think I see about 1/4 of the game screen. So I can't see all the parts of the interface I need to change the resolution. Maybe I need to change something in the config to get it to full screen or something so I can change the resolution?

Perhaps? Can you tell us what kind of Mac and GPU you're using, for starters?

Sounds like a good idea.

MacBook Pro (Retina, 15-inch, Mid 2015)
2.5 GHz Quad-Core Intel Core i7
16 GB 1600 MHz DDR3

AMD Radeon R9 M370X 2 GB
Intel Iris Pro 1536 MB

Model Name: MacBook Pro
Model Identifier: MacBookPro11,5
Processor Name: Quad-Core Intel Core i7
Processor Speed: 2.5 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Hyper-Threading Technology: Enabled
Memory: 16 GB
Boot ROM Version: 195.0.0.0.0
SMC Version (system): 2.30f2

AMD Radeon R9 M370X:
Chipset Model: AMD Radeon R9 M370X
Type: GPU
Bus: PCIe
PCIe Lane Width: x8
VRAM (Total): 2 GB
Vendor: AMD (0x1002)
Device ID: 0x6821
Revision ID: 0x0083
ROM Revision: 113-C5670E-945
VBIOS Version: 113-C567A1-006
EFI Driver Version: 01.00.945
Automatic Graphics Switching: Supported
gMux Version: 4.0.20 [3.2.8]
Metal: Supported, feature set macOS GPUFamily1 v4
Displays:
Color LCD:
Display Type: Built-In Retina LCD
Resolution: 2880 x 1800 Retina
Framebuffer Depth: 24-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Automatically Adjust Brightness: No
Connection Type: Internal

A fresh install works fine. I just need a way to adjust the full screen / window parameters in the config file, or are these defined elsewhere?

After trying it more a fresh install does not work fine. As long as I stay in full screen it's fine, as soon as I try to change to a window the same thing happens.

Need any more info?

Not off the top of my head, it's just something we'll have to look into, and we haven't had a chance yet. Some current projects have taken a week or more longer than anticipated.

Also, MacOS X 10.15 broke so much stuff, that it having problems in window-mode (when it defaults to full-screen) is at least not a total show-stopper.

We will investigate it sometime soon.

In the mean time, can someone tell me how to trick my setup back into full screen mode?

Ah, found it. config.ini

There's an "Enable Retina Support" setting in Video Options. Does changing that setting make a difference?

Yes, that works great, thank you :)