The app’s code doesn’t get installed to unactivated themes. Once a theme is activated, the code gets automatically installed when the app is opened.
To add the apps code to another theme:
Click on the installation button in the navigation
Here you can choose what theme you want to add our code to. Then press Enable. This will add our apps code to that theme.
If you want to remove the code from a theme select the theme and click disable.
Demo themes will come up as grey and unselectable.