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Event Functions
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function chartMouseDown(e) {

                if ((e.button && e.button === 1) || (e.which && e.which === 2)) {
                    e.preventDefault();
                    var offsets = plot.offset();
                    plot.getPlaceholder().append('<div id="plot-highlight-div"></div>').bind('mousemove', middleMouseMove);
                    $('#plot-highlight-div').bind('mouseup', chartMouseUp);
                    that.highlightContainer.highlighting = true;
                    that.highlightContainer.start = e.clientX;
                    return;
                }

                that.previousXPosition = e.clientX;
                that.previousYPosition = e.clientY;

                if (e.shiftKey) {
                    that.panType = 'vertical';
                    plot.getPlaceholder().bind('mousemove', vertPanChart);
                }
                else {
                    that.panType = 'horizontal';
                    plot.getPlaceholder().bind('mousemove', horPanChart);
                }
            }