Bug 5774 Unpredicatable behaviour on double click in packages view
from EC: If you double click a file in the packages view, it opens the file (technically, compilation unit I believe) -- if not already open. However, if the file is already open, a single click selects it as the active editor tag; a double click expands its structure in the packages view. This is unpredictable behavior ;
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
}
	/**
 	 * Handles key events in viewer.
 	 */
	void handleKeyPressed(KeyEvent event) {
		if (event.character == SWT.DEL && event.stateMask == 0){
			fDeleteAction.update();
			if (fDeleteAction.isEnabled())
				fDeleteAction.run();
		}	
	}
	
	/**
	 * Handles double clicks in viewer.
	 * Opens editor if file double-clicked.
	 */
	private void handleDoubleClick(DoubleClickEvent event) {
		IStructuredSelection s= (IStructuredSelection) event.getSelection();
		Object element= s.getFirstElement();
		
		
		if (EditorUtility.isOpenInEditor(element) == null) {
			if (fOpenCUAction.isEnabled()) {
				fOpenCUAction.run();
				return;
			}
		}
		if (fViewer.isExpandable(element)) {
			if (JavaBasePreferencePage.doubleClockGoesInto()) {