I'm having a similar challenge where I want to drive navigation to other dashboards from a drop down menu, presumably a parameter. The reason for the drop down menu is really more one of design aesthetic to match the navigation of our Website in which we embed Tableau but also because I find the practice of using empty worksheets as "buttons" to navigate a little burdensome.
Did you ever find a solution?
Sorry to reply to your question with another question,
It's not possible to drive anything from a dropdown in Tableau. I haven't checked if 8 provides this functionality yet.
What I have done is two other things instead -
1. I have an embedded webpage in the dashboard. Changing my MAP changes the URL of the webpage, passing in the selected country as a parameter. The webpage itself is actually within my own website. And the webpage has just some simple JS whereby I parse the URL params passed in to give me param1, then do a top.window.location.href = '/myurl/'+param1;
2. I have re-architected the solution! Instead of using measures inside Tableau, I've got my measure as a dropdown OUTSIDE Tableau, and on-change, I reload a different Tableau iframe AND go and ajax-get any other content OUTSIDE Tableau on the same page :-)
Hope that helps. The project is under NDA but if I can help some more with examples, just ask.
I'm due a blog article this week at my company, so I think I'll do the parameter passing to external pages as my article and send a link back here!
My company is LogicSpot - my first name and the company name .com if you want to contact me direct for any reason.
Glad I could act as a catalyst to get your blog post completed! I'll take a look over the weekend. Also, thanks for suggestions on ways to tackle the parameter/URL problem. I have always planned on moving filters and parameters onto our website anyway. This is one more reason to do this sooner rather than later.
Have a good weekend.