Unable to edit a webpage link in Numbers on a Mac

I want to edit a webpage link that I created in a cell in Numbers on an iMac. After creation the link appears to work fine. Now I want to edit it (change its Display text, say). The Edit Link menu item is supposed to appear in the context menu that shows when I right click on the link's Display text within the Numbers cell. When I right click on the cell, not the Display text, I get a context menu that does not show an Edit Link item. I have tried different ways of selecting the Display text but all these attempts only activate/operate the link (go to the webpage). I am unable to place the insertion point in the Display text as a first step in selecting the text. How can I edit the link if I cannot select its Display text?