I would like to be able to configure a non-shared tooltip so that the tooltip only appears to the left or right of the point. I was able to modify the highcharts code for a custom positioner, by forcing it to swap() at the end of the routine.

[code]
tooltipPositioner = function (labelWidth, labelHeight, point) {
var chart = this.chart,
distance = this.distance,
ret = {},
swapped,
first = ['y', chart.chartHeight, labelHeight, point.plotY + chart.plotTop],
second = ['x', chart.chartWidth, labelWidth, point.plotX + chart.plotLeft],
// The far side is right or bottom
preferFarSide = point.ttBelow || (chart.inverted && !point.negative) || (!chart.inverted && point.negative),
/**
* Handle the preferred dimension. When the preferred dimension is tooltip
* on top or bottom of the point, it will look for space there.
*/
firstDimension = function (dim, outerSize, innerSize, point) {
var roomLeft = innerSize < point - distance,
roomRight = point + distance + innerSize < outerSize,
alignedLeft = point - distance - innerSize,
alignedRight = point + distance;

                        if (preferFarSide && roomRight) {
                            ret[dim] = alignedRight;
                        } else if (!preferFarSide && roomLeft) {
                            ret[dim] = alignedLeft;
                        } else if (roomLeft) {
                            ret[dim] = alignedLeft;
                        } else if (roomRight) {
                            ret[dim] = alignedRight;
                        } else {
                            return false;
                        }
                    },
                    /**
                     * Handle the secondary dimension. If the preferred dimension is tooltip
                     * on top or bottom of the point, the second dimension is to align the tooltip
                     * above the point, trying to align center but allowing left or right
                     * align within the chart box.
                     */
                    secondDimension = function (dim, outerSize, innerSize, point) {
                        // Too close to the edge, return false and swap dimensions
                        if (point < distance || point > outerSize - distance) {
                            return false;

                            // Align left/top
                        } else if (point < innerSize / 2) {
                            ret[dim] = 1;
                            // Align right/bottom
                        } else if (point > outerSize - innerSize / 2) {
                            ret[dim] = outerSize - innerSize - 2;
                            // Align center
                        } else {
                            ret[dim] = point - innerSize / 2;
                        }
                    },
                    /**
                     * Swap the dimensions
                     */
                    swap = function (count) {
                        var temp = first;
                        first = second;
                        second = temp;
                        swapped = count;
                    },
                    run = function () {
                        if (firstDimension.apply(0, first) !== false) {
                            if (secondDimension.apply(0, second) === false && !swapped) {
                                swap(true);
                                run();
                            }
                        } else if (!swapped) {
                            swap(true);
                            run();
                        } else {
                            ret.x = ret.y = 0;
                        }
                    };

                // Under these conditions, prefer the tooltip on the side of the point

// if (chart.inverted || this.len > 1) { force it to swap()
swap();
// }
run();

                return ret;

            };

[/code]