Sync items can be dependent on each other. In the Advanced tab of the sync settings you may add a dependency by selecting the + button beside the respective text field or by typing a sync item’s title.
When starting a sync item which has one or more dependencies that haven’t been completed yet (i.e. they have no green badge), those will be run first. As soon as all dependencies are successfully completed, the sync item will start running. If a dependency encounters some errors or is canceled, the sync item will be delayed until the dependency is completed.
You may create dependency chains as long as they are not circular. For example, sync item A can depend on B which in turn can depend on C, but C may not depend on A again. Sync items causing a circular chain are automatically disabled in the dependencies menu.
When starting a sync from the context menu or the toolbar, you may hold the Alt/Option key in order to temporarily skip the dependencies.