The Problem
I am trying to add a tool tip to a flowchart PDF I am making using the Tikz library so that ideally it displays when one hovers over the flowchart box. However, I don't know how to make that happen.
I don't know if I should be using this, but I have found this library called pdfcomment that allows tool tips to be placed over words it seems, but in my use case combined with Tikz it doesn't work exactly as I'd like it to.
Minimal Example of my Code
\documentclass{article}
\usepackage[latin1]{inputenc}
\usepackage{tikz}
\usepackage{pdfcomment}
\usetikzlibrary{shapes,arrows}
\begin{document}
\pagestyle{empty}
% Define block styles
\tikzstyle{block} = [rectangle, draw, fill=blue!20,
text width=5em, text centered, rounded corners, minimum height=4em]
\begin{tikzpicture}[node distance = 2cm, auto]
% Place node[![enter image description here][1]][1]
\node [block] (init) {\pdftooltip{initialize model}{Hello World}};
\end{tikzpicture}
\end{document}
And this code resulted in the following PDF:

As you can see the small dashed rectangle shows where the tool tip will trigger on hover and it does not wrap to the second line. It even extends past the boundaries of the box as if the word within the flowchart were on one line.
Is something that would look like the following possible?
\pdftooltip{\node [block] (init) {Hello World Node}}{Hello World Tool Tip}
Ideal behavior would be if the user is able to trigger the tool tip by hovering over the flowchart's rectangle itself rather than the word within the rectangle.
The Question
Is it possible to make it so that when one hovers over the flowchart rectangle, it will trigger a tool tip message? If so, how does one accomplish that?