src/vs/base/browser/ui/scrollbar/abstractScrollbar.ts/AbstractScrollbar/_onElementScrollPosition
class AbstractScrollbar:	protected _onElementScrollPosition(elementScrollPosition: number): boolean {
		if (this._scrollbarState.setScrollPosition(elementScrollPosition)) {
			this._visibilityController.setIsNeeded(this._scrollbarState.isNeeded());
			this._shouldRender = true;
			if (!this._lazyRender) {
				this.render();
			}
		}
		return this._shouldRender;
	}