thank you very much for your detailed explanations! You gals and guys in the forum very kind and helpful. But I don't want to waste your (freetime) ressources. I was looking in the docs about my problem but couldn't find something. Maybe I missed it?
I have to thnk about a tutorial/howto for the future when I am more comfortable with JabRef. Most of the articles about JabRef are focusing to much on the bib-file thing and the concept behind it instead of telling how to use JabRef in real use cases most efficient.
"marking on import"
This is a interesting behaviour. I saw a option that all markes will gone when importing new entries. But I think the (import) marks should gone after closing (re-open) the database, too. What do you think? Should I open a FeauterReqeust for that?
Ah, I haven't looked in that menu. I was looking in the "Preferences" where there is no equivalent for that. In my opinion as a software designer this is a bug. All available options in the groups pane should be available in the "Preferences" (maybe under "Groups"), too.
Maybe I was clicking to much around in the past: Is this gray-out-behaviour default? If so this should be overthink, too. IMO this isn't a behaviour a "normal user" (comming from other literatur software) would expect. In combination with the rainbow-colors it totaly confuse a user.