src/vs/editor/browser/controller/mouseTarget.ts/MouseTargetFactory/getMouseColumn
class MouseTargetFactory:	public getMouseColumn(relativePos: CoordinatesRelativeToEditor): number {
		const options = this._context.configuration.options;
		const layoutInfo = options.get(EditorOption.layoutInfo);
		const mouseContentHorizontalOffset = this._context.viewLayout.getCurrentScrollLeft() + relativePos.x - layoutInfo.contentLeft;
		return MouseTargetFactory._getMouseColumn(mouseContentHorizontalOffset, options.get(EditorOption.fontInfo).typicalHalfwidthCharacterWidth);
	}