Silverlight 2 WPF XAML XAP architecture

Question

I am working on third party silverlight application. What it does is it fetches visio document from folder structure and shows it on silverlight application on web browser. Structure of silverlight is as follows.

 < Silverlight div>
          <source is XAP file >

 <div end>

Above code is on hosted aspx.

So i converted xap to zip and got all source files. Within xap file i found relative page hosted on silverlight. (atleast thats my understanding for now and i believe its WPF after research on elements involved) Further visio document is mapped to canvas on page and the structure of canvas is as follows.

  <wpf code>
       --control for visio diagram
        <canvas binding to FrameworkELement Type>

        <canvas end>
  <wpf end>

I did further research on canvas and FrameworkElement. My understanding is that application is fetching document details from folder structure and creating a drawing based on shapes involved on it and returning FrameworkELement type object back to canvas element which is shown on browser silverlight application.

Some of the drawing shapes have right click enabled on those. Is there a way that I could enable left click on new element that i would add ? What is the standard way of hosting Visio document on silverlight. And is it possible that my understanding about application is correct so far? I am trying to tweak vendor application for one active button on silverlight platform. Any help or guidance would be greatly appreciated. Thank you.