Correct, this view can be displayed in the KNIME WebPortal which is part of the commercial KNIME Server extension. To have this view available in the web, you would need to collapse the node (or workflow) into a so-called sub node and upload the workflow onto the server.
Besides that, I have a problem when I mix standard QuickForm nodes and this "interactive" nodes. Interactive nodes that are part of SubNode are shown correctly, but any additional standard QuickForm nodes are not shown on WebPortal. Is this normal behaviour? If so, why?
You are right: This is badly documented mostly because this is still somewhat in stealth mode and not meant for production use. All the new nodes are in the "Labs" category and so are the "subnodes".
This is changing and we expect them to be of production quality in the December release.
To give some more idea about how to use them: If you create a workflow that contains the new Quickform nodes (the one in "Labs") then this workflow will be driven by a new wizard execution. That new execution has a couple of benefits (like better controlling via variables, default values, parameter validation, interactive views and ability to see/select data, looping in the wizard) but also a couple of quirks (like not properly swapping those jobs to disc when the server restarts or the fact that credentials are not yet supported).
In order to use them you would need to collapse all the "Labs" quickform nodes, which define a wizard page, into a subnode. Each subnode in your workflow defines a wizard page. Old Quickforms are ignored/not shown in the wizard. Also important: A subnode gets completely executed before it's shown in the wizard. That is different to the old wizard execution but is required to support interactive views and also to guarantee that all QFs see the current/actual data so be careful not to do any heavy computation in those wizard subnodes.
Attached is a simple example (which is also part of each new server installation starting with server 4.1).