Synchronizing

When you "Synchronize", the resulting viewer has three modes from which you can select:

These modes are represented by icons along the top of the Synchronize view.

If you have incoming changes when you synchronize, you'll start off in Catch Up mode; otherwise, you'll start in Release mode with your outgoing changes. In either mode you will see conflicts since a conflict is both an incoming and an outgoing change. To facilitate finding and correcting conflicts, you can filter out outgoing and incoming changes via the Show Only Conflicts button.

Modes not only filter the set of visible changes but also appropriately restrict the set of operations available: you can only catch up in Catch Up mode, and release in Release mode. 

The advantages to modes are:

Catch Up/Release mode combines these two modes in a single view. You will see both incoming and outgoing changes and can both catch up and release. You will remain in this mode with future synchronizations until you close the view.  The advantage to using this dual mode is you can do either task as you choose. The disadvantage is that performing a simultaneous bi-directional merge is often complicated. In addition, you risk accidentally releasing a conflict when you meant to catch up to it.

You can choose to always use Catch Up/Release mode on the workbench preferences page (Window > Preferences > Workbench > Team).