code: private static Stack<UIContext> getStack() {
  		Stack<UIContext> stack = CONTEXT_STACK.get();
  
  		if (stack == null) {
  			stack = new Stack<>();
  			CONTEXT_STACK.set(stack);
  		}
  
  		return stack;
  	}
docs: Retrieves the internal stack, creating it if necessary.
  
  @return the internal stack