<br> <br>
<input type="button" value="Unzoom" onclick="unzoomGraph()">
<br> <br>
- <input type="button" value="pan frame 0" onclick="panEdgeFraction(0)">
+ <input type="button" value="pan frame null" onclick="panEdgeFraction(null)">
<input type="button" value="pan frame 0.1" onclick="panEdgeFraction(0.1)">
<input type="button" value="pan frame 0.5" onclick="panEdgeFraction(0.5)">
</p>