code: public void setTolerance(String tolerance) {
          this.tolerance = tolerance;
          Element elt = getElement();
          if (isInitialized(elt)) setTolerance(elt, tolerance);
      }
docs: @param tolerance - Default: "30,15,30,15"
  <br> Sets the minimum distance from the edge of the window for the corresponding edge
  of the popup. By default, the values above will be used for the distance from
  the top, right, bottom, and left edge of the window, respectively.
  
  <br> You can specify a value for this option in one of four ways:
  <br> 1. Empty string, null, or some other falsy value. This will cause the popup to revert
  to the above default values.
  
  <br> 2. A single number. This number will be used for all four edge tolerances.
  
  <br> 3. Two numbers separated by a comma. The first number will be used for tolerances
  from the top and bottom edge of the window, and the second number will be used for tolerances
  from the left and right edge of the window.
  
  <br> 4. Four comma-separated numbers. The first will be used for tolerance from the top edge,
  the second for tolerance from the right edge, the third for tolerance from the bottom edge,
  and the fourth for tolerance from the left edge.