Is this possible to do? I use three monitors - each independently driven from my Mac Studio.
During flight all three monitors are used for one continuous display of the flight. I would like to switch to Nabigraph from time to time to check data but not take up real estate during the actual flight
The Navigraph window doe not seem to allow it to be resized or step down sized or hidden - standard features in OSX. What am I missing here please
I am not entirely sure what you mean. This is not app-specific behaviour, but rather comes down to how you prefer to use your OS (in this case macOS).
If you want to minimize the window, you should be able to press ⌘ + M while having the Charts app focused to do so. You can also use the window controls in the top left of the window where the button colors have the following meaning: