No the dashboarddemo is not in the addon builder generated app.
I created the dashboard from the search app ("Create dashboard"), then i created a AddOn using addonbuilder.
then from the setting menu i added the link to the dashboard which i had already created.
Now when I am downloading the "addonexample.spl" file and installing in another machine with splunk there i am getting the Addon with the "Dashboard" on the navigation bar but on clicking the dashboard called "dashboarddemo" is missing.
If i go and create the dashboard (called "dashboarddemo") manually then the nav link from Addon works and opens up the dashboard.
Your app should have your dashboard files and navigation file,
Just follow these steps:
1) Create folder if not exists SPLUNK_HOME/etc//apps/default/data/ui/views/
Reference for folder Structure: http://dev.splunk.com/view/webframework-developapps/SP-CAAAEUC
2) Copy dashboarddemo.xml file:
To : SPLUNK_HOME/etc//apps/default/data/ui/views/
3) Create folder if not exists: SPLUNK_HOME/etc//apps/default/data/ui/nav/
Create a default.xml file and paste navigation XML.