src/vs/base/browser/ui/scrollbar/verticalScrollbar.ts/VerticalScrollbar/onDidScroll
class VerticalScrollbar:	public onDidScroll(e: ScrollEvent): boolean {
		this._shouldRender = this._onElementScrollSize(e.scrollHeight) || this._shouldRender;
		this._shouldRender = this._onElementScrollPosition(e.scrollTop) || this._shouldRender;
		this._shouldRender = this._onElementSize(e.height) || this._shouldRender;
		return this._shouldRender;
	}