I noticed this while trying to select a face and edges inside a component. I often double click to select a face this way but when I tried in this configuration SU opened the group behind the face. The face and edges can be selected by selection box however. Easy enough to work around, but odd.
Note that double click selection works on loose geometry nearby.
Shep
You can double click one edge to prevent this behaviour.
I find this a lot; if the loose geometry lies on top of a group.component, then double-clicking to select the face and all connected edges of loose geometry will instead edit the underlying group.
I have 2 work-aroundās I normally use:
You could also select and move the underlying group away from the geometry (select move and type in a specific value - then itās easy to move it back again by the same amount)
Or you could draw a line and make it into a group before adding in the loose geometry (so that when you are adding it, itās already in a group and the double click will work to select as you expect)
SketchUp is trying to tell you make that loose Geometry into a component!
Probably, not intended behavior. But as @Cotty said, you can avoid it by clicking the edge[quote=āgadget2020, post:3, topic:18003ā]
hide the underlying group - down side is that itās another three clicks to un-hide it again.
[/quote]
To add on this. you can do āhide rest of modelā from View.
lol - thatās what I am trying to do when double clicking: select it all to make it a group/component 
use āLock/Unlockā instead of āHide/Un-hideā for less clicksā¦
john