In the "Package Explorer" view, hit the down-pointing arrow, then -> Package Presentation -> Hierarchical.
Much, much clearer.

Hmmm... I thought it was the default. But thank you very much in the name of all.
Then let me tell you another nice hint: Klick "Select Working Set..." in this same "downArray" menu. Then click "New", type the name and add all the Projects, that you currently want to see in the Package Explorer. Activate the Working Set And you will have a "virtually" cleaned up Workspace

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Marvin