run-app's #:windows gives the windows a model has. The app opens a window
when it is first in the list, patches its view and title while it stays,
and closes it when it is gone. A click on its close button sends its
on-close message, and the model closes it. A #:modal window is a dialog
over the main window, so a dialog of the program's own is a window whose
state is in the model.
Windows wait for the main window to be shown, because a dialog cannot
belong to a hidden one, and the program ends when the main window closes.
Key shortcuts and commands such as focus reach the other windows too, and
#:screenshot saves a picture of each one beside the main window's.
🤖 Generated with [ECA](https://eca.dev) (anthropic/claude-opus-4-8)
Co-Authored-By: eca-agent <git@eca.dev>
