changed default graphics controller for macos
On MacOS the virtual machine would not update its display unless it was deselected and then selected again. I changed the default graphics controller for the virtual machine and that solved the issue.
@evanblasy I have created VMs using this repository on Windows, and then loaded them into a macOS 10.14.6 system (a bit old of a version now, I know), and I have also created VMs using this repository on macOS 10.14.6, then tried loading them on Windows 10. I had problems in the created-on-macOS direction, but not in the created-on-Windows direction, where the resulting VM did have the display type equal to "VBoxVGA". For example, I could run 'top' in a terminal window, switch to another macOS window that did not completely cover up the VM window, and I could see the output of 'top' still updating every 3 seconds as expected, without having to select it.