If you notice that the part or Sub-assembly in your FeatureManager Design Tree icons look like this:
Actually in SOLIDWORKS assemblies, envelopes serve as selection and reference components. The bill of materials and mass characteristics do not take into account envelopes (parts or assemblies). It is Uses to:
- Keep-out areas or volumes
- Design to
- Size, position, and mates
- Selection sets for configurations from different sub-assemblies
- Visibility
In order to change it back to default Part, you may need to:
1. Right-click the component and then select Component Properties.
2. Uncheck the envelope selection on bottom right of the window.
After that your part or sub-assembly will turn back to normal and you may continue to do editing process without limitation.