I added a second menu to my page and now I can't seem to access the properties panel in DW for each. With one menu in split view mode I would click on the menu in the Design window and the Edit menu properties panel would appear. With two menus I can't seem to activate the properties panel for each.

Hello Simon,

There shouldn't be a problem accessing the menu options in the property inspector as each of the menus has its own unique id:
<div id="navmenu1" class="dmxNavigationMenu"> ....
<div id="navmenu2" class="dmxNavigationMenu">

IS there an alternative way of showing the properties panel other than clicking on the menu in design view? This no longer works when you have more than one menu on the page.

It works just fine, there must be some problem with your DW, maybe?
If you click on any of the menu divs in Split view -
<div id="navmenu1" class="dmxNavigationMenu"> for example, Do you see anything in the properties inspector?

In speaking with Teodor on live support I was able to find out the problem. The extension creates a snippet of JavaScript code in the body of your page and positions it immediately below the menu code. Trying to be diligent I had moved this code to the bottom of the page. When I moved it back the properties menu was accessible again!

So the lesson of the day is...DON'T MOVE THE CODE []