You can control how the Workbench responds to single and double clicks. To do this:
The effect of these selections varies by view. For example, in one of the navigation views:
The checkboxes under the Single click radio button further refine the single click behavior. Checking Select on hover will cause the resource to be selected if you hover over it with the mouse. Checking Open when using arrow keys will cause the resource to be opened if you use the arrow keys to navigate to it.