Step to reproduce:

1.Create an empty assy1

2.Save it on disk

3.Create an empty assy2

4.Save it on disk

5.Insert a couple of assy2 into assy1

6.Select one of the planes (or origin) of assy1

Graphic area highlights the selected entity for each assy2 inserted into assy1 even if the selected entity is in assy 1.

Graphic card accelaration unrelated: Tried with both enable and disabled in system option.
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