Bug 63898 [reconciling] Multiple threads calling IJavaReconcilingListener#reconciled() at the same time
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/JavaReconciler.java
private Control fControl;
		
		public ActivationListener(Control control) {
			fControl= control;
		}
		/*
		 * @see org.eclipse.swt.events.ShellListener#shellActivated(org.eclipse.swt.events.ShellEvent)
		 */
		public void shellActivated(ShellEvent e) {
			if (!fControl.isDisposed() && fControl.isVisible() && hasJavaModelChanged())
				JavaReconciler.this.forceReconciling();
		}
		
		/*
		 * @see org.eclipse.swt.events.ShellListener#shellDeactivated(org.eclipse.swt.events.ShellEvent)
		 */
		public void shellDeactivated(ShellEvent e) {
			setJavaModelChanged(false);
		}
	}
	
	/**
	 * Internal Java element changed listener
	 * 
	 * @since 3.0
	 */
	private class ElementChangedListener implements IElementChangedListener {