Designer 2010 Workflow does not overwrite old version when published

Whenever I publish a workflow from the Designer, the workflow will create a new workflow instead of updating the old one.

For example:

• Workflow A is published as a list workflow and can be manually started by users


• Workflow A is published again. Users can now start two workflows "Workflow A" and "Workflow A (1)" instead of just the new one

Is there a setting to turn on overwriting for workflows?