part has had a lot of additions and subtractions to reach final part. Took tree all the way back to initial extrusion and shell is still there.
It's not shelled !!!
Your face is transparent giving the illusion it is shelled.
Just select the face and turn off transparency.
If you can't select the face go into settings and selection options then uncheck - 'Enable selection through transparency'. You should now be able to select the transparent face.
Hope this helps.
If you hold shift down and hover over where the face should be, you will notice you can select it.
Once it has been selected you can right click and change transparency, and the face will come back.
I didn't know about that 'Shift' trick - thanks James - will be very useful.
Problem has been solved. Never had a face set to transparent before.
I am sure you do not need a such a long tree for this simple part. It can be completed in a few steps.
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