If I copy and paste my group into another Sketchup file, that group ends up having the Type to be undefined. When I drag the file itself (from my documents) into the opened Sketchup file, the group now has a definition.
Does it matter if there is a definition or if the group is undefined?
I want to know if there is any significant advantage to having one over the other.
By dragging the file which contains the group, you’ re adding a ‘model’ wrapper around the group. It is the same as a File->Import.
So you are actually importing a Component-file, which contains the Group.
If you ‘enter’ the now wrapped component, you can select the group.
Learn more about groups and components here:
Just to back up what @MikeWayzovski is saying, look at your screenshot, one is a group and one is a component.
And to better understand the hierarchy of all the grouped entities (groups and components) in your modeling space you can open the ‘Outliner’.
The learning power from the forum is truly amazing, thank you for posting these screenshots.