private String VerifyDataValue(double time,long expect,PlotData d) {
	DigitalPlotCoordinate c = (DigitalPlotCoordinate)d.FindCoordinate(time);
	if (c == null || !c.Match(expect)) {
	    String e = d.toBinaryString(expect);
	    StringBuffer aa = new StringBuffer(c == null ? "... no value ..." : "0b");

	    // highlight mismatches in red
	    if (c != null) {
		String a = c.toBinaryString();
		boolean red = false;
		for (int i = 0; i < e.length(); i += 1) {
		    int ch = a.charAt(i);
		    if (e.charAt(i) != ch) {
			if (!red) {
			    aa.append("<font color=red>");
			    red = true;
			}
		    } else if (red) {
			aa.append("</font>");
			red = false;
		    }
		    aa.append((char)ch);
		}
		if (red) aa.append("</font>");
	    }

	    return
		"<font size=5>Node value verification error...</font><tt><ul>"
		+"<li>node(s):&nbsp;&nbsp;"+nodes
		+"<li>time:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"+UI.EngineeringNotation(time,3)+"s"
		+"<li>expected:&nbsp;0b"+e
		+"<li>actual:&nbsp;&nbsp;&nbsp;"+aa.toString()
		+"</tt></ul>";
	}
	return null;
    }