add "keep running in background after all tabs were closed" option

[IvoryJam]

yakuake does this and it makes it faster to open after closing with exit or the shortcut ctrl-d

[pesader]

@amezin Do you have an idea of how to implement that? I also want this feature, so I could submit a PR if you give me a general direction :)

[amezin]

Changes outside application.js should not be necessary.

Currently, the code there assumes that the window always exists. So it should be modified to work even when this.window is null (and also it should likely create the window in activate() instead of startup()). In particular, Gio.Actions shouldn't be simply copied from the window object, instead, proxy actions (that also create the window when necessary) should be created.

To keep the app running - see https://gjs-docs.gnome.org/gio20/gio.application#method-hold

[amezin]

Currently, the code there assumes that the window always exists. So it should be modified to work even when this.window is null (and also it should likely create the window in activate() instead of startup()). In particular, Gio.Actions shouldn't be simply copied from the window object, instead, proxy actions (that also create the window when necessary) should be created.

All of this is already implemented - to make D-Bus activation work

Also, Gio.Application has a inactivity-timeout property - maybe setting that to a large value should be enough