Bug 488231 - Extensions editor tree collapses after switch to source
view

Check if root node is already created. If so, do not re-create it.
Otherwise tree collapses after save if source view of "plugin.xml" was
visible at least once.

Change-Id: I7c279d84d0359af0e0c9f6b869db748922a62480
Signed-off-by: Arne Deutsch <arne@idedeluxe.com>
diff --git a/ui/org.eclipse.pde.core/text/org/eclipse/pde/internal/core/text/plugin/PluginModelBase.java b/ui/org.eclipse.pde.core/text/org/eclipse/pde/internal/core/text/plugin/PluginModelBase.java
index 59fd7d0..1333674 100644
--- a/ui/org.eclipse.pde.core/text/org/eclipse/pde/internal/core/text/plugin/PluginModelBase.java
+++ b/ui/org.eclipse.pde.core/text/org/eclipse/pde/internal/core/text/plugin/PluginModelBase.java
@@ -40,6 +40,9 @@
 	}
 
 	public IPluginBase createPluginBase(boolean isFragment) {
+		if (fPluginBase != null) {
+			return fPluginBase;
+		}
 		if (isFragment) {
 			fPluginBase = new FragmentNode();
 			fPluginBase.setXMLTagName("fragment"); //$NON-NLS-1$