title: Extra line drawn in Flotchart using TickRotor plugin
body: <p>I am trying to create a stacked bar chart using FlotChart.
  My challenge is to create a multiple x-axis labels up to 5 layers.
  So, I tried to use TickRotor plugin (initially because I wanted to rotate the labels vertically).</p>
  
  <p>Now, I wanted to draw some lines and tweaked some functions in TickRotor. However, a weird line is drawn somewhere in my chart. Could you please help me what's happening?</p>
  
  <p>Here's the "else" part of the <code>plot.hooks.draw.push(function (plot, ctx)</code> :</p>
  
  <pre><code>if (ticks.length == 0) {
      return;
  }
  xaxis = plot.getAxes().xaxis;
  var box = xaxis.box;
  var tick, label, xoffset, yoffset;
  var showWeek = false;
  for (var i = 0; i &lt; ticks.length; i++) {
      tick = ticks[i];
      if (!tick.label) {
          continue;
      }
      ctx.save();
      ctx.font = font;
      if (rotateTicks &lt;= 90) {
          // Center such that the top of the label is at the center of the tick.
          xoffset = -Math.ceil(Math.cos(radsAboveHoriz) * tick.height) - 10;
          yoffset = Math.ceil(Math.sin(radsAboveHoriz) * tick.height) - 10;
          ctx.translate(Math.round(plot.getPlotOffset().left + xaxis.p2c(tick.v)) + xoffset,
                        box.top + box.padding + plot.getOptions().grid.labelMargin + yoffset);
          ctx.rotate(rotateTicksRads);
      } else {
          // We want the text to facing up, so we have to
          // rotate counterclockwise, which means the label
          // has to *end* at the center of the tick.
          xoffset = Math.ceil(Math.cos(radsAboveHoriz) * tick.height)
                    - Math.ceil(Math.cos(radsAboveHoriz) * tick.width);
          yoffset = Math.ceil(Math.sin(radsAboveHoriz) * tick.width)
                    + Math.ceil(Math.sin(radsAboveHoriz) * tick.height);
          ctx.translate(Math.round(plot.getPlotOffset().left + xaxis.p2c(tick.v) + xoffset),
                        box.top + box.padding + plot.getOptions().grid.labelMargin + yoffset);
          ctx.rotate(-radsAboveHoriz);
      }
      var ticksMe = tick.label.split(" ");
  
      // draw labels
      ctx.fillText(ticksMe[0], 0, 0);
      if(showWeek){
          ctx.fillText(ticksMe[1], xoffset, yoffset * 2);
          showWeek = false;
      }
      else{
          showWeek = true;
          ctx.moveTo(-4,-10);
          ctx.lineTo(-4,(yoffset * 2));
          ctx.stroke();
      }
  
      ctx.restore();
  }
  </code></pre>
  
  <p>Here's the image that show's where the weird line is drawn :
  <img src="https://i.stack.imgur.com/tVrA4.png" alt="Weird Line is Drawn Image"></p>