src/vs/editor/browser/controller/mouseHandler.ts/MouseHandler/_createMouseTarget
class MouseHandler:	protected _createMouseTarget(e: EditorMouseEvent, testEventTarget: boolean): IMouseTarget {
		let target = e.target;
		if (!this.viewHelper.viewDomNode.contains(target)) {
			const shadowRoot = dom.getShadowRoot(this.viewHelper.viewDomNode);
			if (shadowRoot) {
				target = (<any>shadowRoot).elementsFromPoint(e.posx, e.posy).find(
					(el: Element) => this.viewHelper.viewDomNode.contains(el)
				);
			}
		}
		return this.mouseTargetFactory.createMouseTarget(this.viewHelper.getLastRenderData(), e.editorPos, e.pos, e.relativePos, testEventTarget ? target : null);
	}