in packages/timebrush/src/TimeBrush.ts [469:490]
private renderBrush(height: number) {
this.brush.x(<any>this.x);
// Need to recreate the brush element for some reason
d3.selectAll(this.element.find(".x.brush").toArray()).remove();
this.brushEle = this.context.append("g")
.attr("class", "x brush")
.call(this.brush)
.selectAll("rect")
.attr("height", height + 7)
.attr("y", -6);
this.brushGrip = d3.select(this.element.find(".x.brush")[0])
.selectAll(".resize").append("rect")
.attr("x", -3)
.attr("rx", 2)
.attr("ry", 2)
.attr("y", (height / 2) - 15)
.attr("width", 6)
.attr("fill", "lightgray")
.attr("height", 30);
}