Part of the problem is solved - I can see now the TabIndex-Entry in the properties of an item in the Vaadim designer. I didn’t see it before because the Vaadim Designer had loaded an icomplete configuration by recovering from one of its many crashdowns.
At least Vaadim Designer runs stable now, before it was difficult to even load it.
My other issue is still unsolved: Where do I find the list of all changes in version 8.0.0? Vaadim team, please provide full documentation! How are we supposed to handle Vaadim 8 without it?
Well, in Vaadin 8, a lot have changed. Basically all Fields have been totally redesigned from grounds up (and old ones have been moved into vaadin-compatibility jar and made deprecated). That may also be the case why you are seeing the setTabIndex() deprecated - in fact the whole component is deprecated and you should gradually replace the Field components from v7 to the new ones. Beware - the API is quite different so it’s not a straightforward process.