Not all Groups are part of the model. In particular, if you have functional Groups, those are likely not going to be a part of the model. That’s not how the model is designed to work. The model is supposed to model the “real world” and as such a piece of equipment can’t physically be in two different locations at the same time. Of course, we all know that might not necessarily be true in the real world but, as with any model, certain constraints need to be applied.
So as a general rule of thumb, in the model, you wouldn’t model something like “All First Floor Lights” because the model already encodes that information. However, on your UI or in your Rules you might want to treat all the first floor lights as one. In that case you can still have the Group. It just won’t be a part of your model.
And that’s fine. Not everything has to be a part of the model.
Without a lot more specific details there’s really no way to tell whether this is the expected behavior or not. It doesn’t sound like expected behavior but there are a lot of variables. I recommend filing an issue on the openhab-webuis and gather all the information requested in the template.
One would ask why you have a large number of similar type rules instead of one generic rule that handles all of this in the first place. But in either case, it’s the same code whether it’s running from .rules files or when running in a Script Actions. If you can’t figure out the java.time stuff in the .rules files there should be no expectation that it’ll be any different in UI created script actions.
To more easily create rules through the UI, create the first one, click on the code tab, copy the YAML to the clipboard. Create the next rule, open the code tab, paste the previous rule and edit to make the new rule. Or stick to .rules file. You don’t have to move rules to the UI.
It’s not.
Just to be clear, what type of Item does the Thing Channel require? It will only list Items that are compatible with the Channel.
It’s strongly encouraged as there is a lot of functionality like automatically creating the overview pages require it. It’s also easier to create a bunch of Items from a Thing and stuff like that. But it is in no way required to build a model.
That should still work because sitemaps are still supported and sitemaps do it through the label. MainUI Pages use metadata.