Bug 197113 Project Explorer drag and drop selection not working properly
Create a new java project. Open Project Explorer. Create 2 new classes - Test1 and Test2. Close the java code editors. Select Test1.java in the project explorer. Select Test2.java by doing a mouse down only (so Test1.java still appears highlighted) then drag Test2.java into the code editor area ()- Test1.java is displayed. This only occurs in the Project Explorer, the package explorer works fine.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonViewer.java
/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.AbstractTreeViewer#setSelectionToWidget(java.util.List, boolean)
	 */
	protected void setSelectionToWidget(List v, boolean reveal) {
		clearSelectionCache();
		super.setSelectionToWidget(v, reveal);
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.AbstractTreeViewer#handleDoubleSelect(org.eclipse.swt.events.SelectionEvent)
	 */
	protected void handleDoubleSelect(SelectionEvent event) {
		clearSelectionCache();
		super.handleDoubleSelect(event);
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.StructuredViewer#handleOpen(org.eclipse.swt.events.SelectionEvent)
	 */
	protected void handleOpen(SelectionEvent event) {
		clearSelectionCache();
		super.handleOpen(event);
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.StructuredViewer#handlePostSelect(org.eclipse.swt.events.SelectionEvent)
	 */
	protected void handlePostSelect(SelectionEvent e) {
		clearSelectionCache();
		super.handlePostSelect(e);