If you look closely at the title of the Synchronize view you will see that we have started in Incoming Mode (see #1). This is because there are changes in the repository that we should first integrate before committing our own changes.
It is important to first update to changes made to the repository, retest with those changes loaded locally with your soon-to-be-committed changes and then commit your changes. By first taking the latest repository changes, and retesting, it helps to ensure that the changes you are about to commit will actually work with the current state of the repository.
Updating
Making our own changes