I have documented some exploration my UI team has done to solve this issue and added an idea to the Mendix forum. Please upvote it here: https://forum.mendix.com/link/ideas/1218
You can use the Private Mendix App store for it. This way you can upload your own module with the Cross Application CSS in the App Store and download the new version in all the applications every time it changes.
Hope it can help ;-)
Since the theme is part of the package I think there is no workaround for what you want. In our company it is just part of the release cycle. When there is a new version of the theme we copy the theme to the project folder and update the setting inside the modeler. Yes, you have to do this for every client environment. But since it is part of the release planning not a big problem. And the theme get's also tested in the test cycle of the new release for that customer. I would not want to upgrade a theme without testing it on that specific client. But that is my opionion.
It works as follows:
- The request handler executes a microflow (similar to what deeplink does).
- The microflow returns a ContentDocument entity which contains: ContentType, Content, CharEncoding and StatusCode attributes.
- In the microflow, our custom (branded) css is retrieved as FileDocument from the database. A new ContentDocument entity is created and the css content, along with other attributes, is copied into the ContentDocument entity.
- The entity is transformed by the request handler into an HTTP response with the contenttype, content, etc for css.
I’m very interested to know if anyone has figured this out?