• Adding/Closing projects
  
• File is modified in the file system
  
• Some action modifies the object model.
  

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<BpelGroup>
    <imports>
        <import>
            <path>c:/test/</path>
        </import>
        <import>
            <path>c:/test/hello/world</path>
        </import>
    </imports>
    <data>
        <element>
            <name>Data Element 1</name>
        </element>
        <element>
            <name>Data Element 2</name>
        </element>
	<element>
            <name>Data Element 3.2</name>
        </element>
	<element>
            <name>Data Element 3.1</name>
        </element>
    </data>
</BpelGroup>

I have a custom project nature whose main artifact is a file in some custom XML format. Additionally I've created an object model representing this artifact. I'm using the CNF to display my model.

Is there a best practice approach to keep the model in sync with the tree view?

I'm thinking of:

Adding/Closing projects
File is modified in the file system
Some action modifies the object model.

Now I understand, you just have to make sure you call the right update/refresh methods on the CommonViewer (associated with the CommonNavigator object [the ProjectExplorer]) when your model changes.