And there are several widgets to integrate Grafana into the openHAB UI available on the community marketplace, e.g. Grafana chart with time ranges (with time range picker) or my fork of it openhab-conf/UI/widgets/community.openhab.org/Grafana_Integration.yaml at main · florian-h05/openhab-conf · GitHub (fullscreen).
I also have a simple full-screen webview widget, see Fullscreen Webview Widget.
There is a GitHub discussion on the WebUI repo, I am super busy right now and will be at least for the next three weeks, however the “Duplicate Item” (and other stuff like Things, Rules) functionality is on my to-do list.
It hasn’t been merged yet, because some REST API improvements are required to make it fully operational, but the code view will come.