When you click on a single word, the right click-menu currently allows several functions that are not available when selecting a phrase. I understand the logic of this if a whole paragraph or even sentence was selected. But at times, you will want to use the lookup right-click function on a short phrase.
For example, I just wanted to lookup Cyril of Jerusalem, but couldn't. In my opinion, the lookup command should be only removed from the right-click menu for medium-long phrases. It should not be removed from short phrases.