Check in the Part/Assembly and all the Components
After bringing about your modifications, with this command you stop working on the document and allow other users to take charge of it for editing.
This command is useful to set in checkin state more than one document at once;
A dialog shows the state of selected documents and lets you choose which document to check in.
Some of them, in facts, could be in a state incompatible with checkin (released or frozen).
This entry is enabled also for generic document if the option
Revisions → Approval →
Create structure history for all the Document types
is checked.
For further information please read the topic States and Actions in the section Revisions.