Hi, tommy
Are you sure you are actually opening the emails with one click on your desktop rather than simply viewing them in the preview pane ? I had WLM at one time (as well as other desktop email clients) and I have never been able to get any of them to "open" mails with a single click. Webmail clients, yes. Offline clients, no. I think that's because offline clients (for whatever reason) reserve single-click functionality for merely selecting the message, not opening it -- unless, as I say, one is viewing email in the preview pane.
If you actually have been able to "open" emails with a single-click in the offline WLM client on your desktop, I, too, would like to know how you got it to do that ! Maybe Ray (Popowich) will have some ideas.