I would like to display collapsable section inside adaptive card. Best element that I can see for that is Action.ShowCard that will expand Container. But all actions can only be rendered at the bottom of the page. What is the good solution to achieve that?
This isn't possible today as Action.ShowCard currently isn't supported in the selectAction property. We haven't nailed down the proper UX.
There is a GitHub issue tracking this, feel free to vote on or add additional requirements. We'll look at prioritizing it depending on need, but this request has indeed come up a few times.