The upgrade from 2.1.0.3 to 2.1.0.4 was working as expected and "designed". Via control panel I remove the old version, started DELPHI and checked if alle references are gone. Also all two subdirs are gone without manually action from.
Installing the new version and all is working well and as designed.
For my case I see this issue as solved and for my opinion the issue can be closed. Thank you Bruno for your hints and help. I see that I have bet on the right horse with this controls and packages to develop my Windows desktop (and if needed Web) apps. 
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