Bug 11814 OpenExternalJavadoc action should not call findElement on JAR
This causes an exception: Java Model Exception: Java Model Status [Invalid path: C:/Java/IBM1.3/jre/lib/rt.jar.] at org.eclipse.jdt.internal.core.JavaProject.findElement(JavaProject.java:435) at org.eclipse.jdt.internal.ui.actions.OpenExternalJavadocAction.run(OpenExternalJavadocAction.java:102) at org.eclipse.ui.texteditor.RetargetTextEditorAction.run(RetargetTextEditorAction.java:103) at org.eclipse.jface.action.Action.runWithEvent(Action.java:473) at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:407) at org.eclipse.jface.action.ActionContributionItem.handleWidgetEvent(ActionContributionItem.java(Compiled Code)) at org.eclipse.jface.action.ActionContributionItem$ActionListener.handleEvent(ActionContributionItem.java(Compiled Code)) at org.eclipse.jface.action.ActionContributionItem$ActionListener.handleEvent(ActionContributionItem.java(Compiled Code)) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java(Compiled Code)) at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java(Compiled Code)) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java(Compiled Code)) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java(Compiled Code)) at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java(Compiled Code)) at org.eclipse.ui.internal.Workbench.run(Workbench.java:698) at org.eclipse.core.internal.boot.InternalBootLoader.run(InternalBootLoader.java:777) at org.eclipse.core.boot.BootLoader.run(BootLoader.java:319) at java.lang.reflect.Method.invoke(Native Method) at org.eclipse.core.launcher.Main.basicRun(Main.java:196) at org.eclipse.core.launcher.Main.run(Main.java:555) at org.eclipse.core.launcher.UIMain.main(UIMain.java:52) 4 org.eclipse.jdt.core 979 Invalid path: C:/Java/IBM1.3/jre/lib/rt.jar.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
if (jdocURL != null) {
				fJavaDocField.setText(jdocURL.toExternalForm());
			}
		}			
	}
	
	
	private void attachmentDialogFieldChanged(DialogField field) {
		if (field == fFileNameField) {
			fNameStatus= updateFileNameStatus();
		} else if (field == fInternalButtonField) {
			IPath jarFilePath= chooseInternalJarFile(fFileNameField.getText());
			if (jarFilePath != null) {
				fFileNameField.setText(jarFilePath.toString());
			}
			return;
		} else if (field == fPrefixField) {
			fPrefixStatus= updatePrefixStatus();
		} else if (field == fJavaDocField) {
			fJavaDocStatus= updateJavaDocLocationStatus();
		}
		doStatusLineUpdate();
	}	
		
	private void doStatusLineUpdate() {
		fPrefixField.enableButton(canBrowsePrefix());
		fFileNameField.enableButton(canBrowseFileName());
		
		
		if (fFullPathResolvedLabel != null) {