I am confused about what multiple desktops mean? I created another desktop using mission control plus icon at the top
But I am unable to open same application twice in different desktops. Is this not possible?
So, multiple desktops do not really behave like desktops but are actually just multiple screens that have a fancy name?
Desktops in MacOS are not like running a different machine. So yes, you are right, you can think of them as multiple screens.
That said, you can have the same application on multiple screens. This requires the application to be able to have multiple parent windows. E.g. this works fine with a browser: Open a second window on desktop 1, enter mission control, and drag the second window to desktop 2. Now you can change desktops and have the same program running on both with different content. Clicking the dock icon will cycle through all open windows of the app, also if they are on different desktops.
This does not work for applications that can have only one parent window, like most email programs or professional editing tools.
But I am unable to open same application twice in different desktops. Is this not possible?
Not all apps support running multiple instances, even if an additional instance can be started; however, if you want to attempt to have another instance of an already running app on a different Desktop then you can try the following:
Open Terminal and use the following syntax:
open -na $appname
Where $appname is in the form of e.g. Calculator or /Applications/Calculator.app, e.g.:
open -na Calculator
Or:
open -na /Applications/Calculator.app
For apps that support running multiple instances, and an instance already running, another instance will run on the same or other Desktop using this method.
By default, the Mac will not open a second instance of an App. If you ask it, by almost any normal method to 'open' again it will in fact bring the original open instance to the front rather than launch a second instance of itself.
This, under most circumstances is not an issue. if you need a new window, you can open that too, inside the same instance.
This is a different paradigm to the traditional MS Windows method, where a new window is often a brand new instance of the app itself. This has changed over the years for such as web browsers, where there is now one 'global' app, with a separate process for each tab. This is much more like the Mac has always done it.
So, back to Spaces [or Desktops: Apple seem to use the two interchangeably, which tends to get a bit confusing].
One App wants to be in one Space. This might be considered a failing, but that's how it is.
If you want to use a second Space, then after you open a second window, grab the title bar & use the key-command to change to the Space you want the window to go to. The window will follow you there.
Unfortunately, it is unlikely to remember that if you Quit & relaunch the app - it will put both windows back on the same Space.
However, for multiple apps, multiple Spaces is a great idea. Launch an app, move it to a Space, then right click it in the Dock > Options > This Desktop & it will henceforth always open in that Space.
