Hello edge users ..
It is a question for the synchronous mirror.
10 000 If one thing can be selected by the Selection Manager.
If two kinds of features like picture?
Why is the mirror to the surface?
How I would suggest.
this is an old issue, You also have to select the top plane for mirroring to get a proper result.
using Sync You have to imagine Your model more in terms of "surfaces belonging together" rather than a classic feature from traditional environment
And so, if You don't select the top plane face, the mirror "feature" can not create a full body on the other side.
To keep this in mind will help You a lot in future sync projects!
really a lot of helpers and tutorials will be found when using the Solid Edge help - Selecting the online tutorials and then You directly are at the Solid Edge training page where everthing could be found
Here is the link too:
There also are the tutorials for printing and self study which I like very much and can recomment too: