Hi Michael! Thank you very much for the explaination and the tips.
That resolved my question very well and already improved my workflow. However one thing:

The selection-filter is very nice and I would want it to be enabled on faces & edges all the time so I don't need to double-click though the solid all the time in order for faces/edges to be selected. Issue is of-course that when I want to select a solid again, I have to reset the selection-filter which is quite cumbersome. For me the perfect workflow in that case would be (A): with selection-filter set to faces&edges, select a face/edge with one click -> (B): click shortcut to trigger script which selects the solid, the edges/faces belong to. For (B) the script 'script:moi.geometryDatabase.selectAll()' looks good at first because it looks like the object is properly selected but then I'm not able to move it (i assume because the actual solid is not selected just the faces and edges). Do you know by chance if that would be possible to select the actual solid?

Thanks a lot again for your help! It's very much appreciated!