Bug 100889 [Undo] - AbstractOperation toString() appends bogus comma
The toString() on AbstractOperation puts commas between undo contexts, and also puts one at the end. It looks pretty bogus in the operation history view. Should clean up to not add the very last comma.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/AbstractOperation.java
public AbstractOperation(String label) {
		this.label = label;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#addContext(org.eclipse.core.commands.operations.IUndoContext)
	 * 
	 * <p> Subclasses may override this method. </p>
	 */
	public void addContext(IUndoContext context) {
		if (!contexts.contains(context)) {
			contexts.add(context);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#canExecute()
	 *      <p> Default implementation. Subclasses may override this method.
	 *      </p>
	 * 
	 */
	public boolean canExecute() {
		return true;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#canRedo()