In order to have a single development environment, capsules on the web client need to be developed with the win client.
This allows to build the capsule only once and have it available on all the different clients (winclient, web, mobile).
Anyway there are still some differences between windows client and web client in visualization.
Here you can find a list of features that does not exist on the web client and that will be eventually implemented in the future
Dataview
Charts
Containers
Procedures
Other