Looked at it during lunch... To me, it appears that you have some kind of a naming convention conflict going on among other issues.
- When the "thumb" symbol is double-clicked on stage, that particular symbol should open up.
- Instead, a symbol called "Inhoud2" opens up... can be verified by the breadcrumb trail in the upper LH corner of the stage... "Stage / Inhoud2"
- With my limited experience, I've never seen that happen before. Would like to, but I just don't have the time to check your entire structure. Just wondering whether there might be unnecessary symbols, etc, in your comp... "thumb" and "Inhoud2" look very similar, if not identical.