src/vs/workbench/contrib/comments/browser/commentThreadZoneWidget.ts/ReviewZoneWidget/_applyTheme
class ReviewZoneWidget:	private _applyTheme(theme: IColorTheme) {
		const borderColor = getCommentThreadWidgetStateColor(this._commentThread.state, this.themeService.getColorTheme()) || Color.transparent;
		this.style({
			arrowColor: borderColor,
			frameColor: borderColor
		});
		const fontInfo = this.editor.getOption(EditorOption.fontInfo);

		// Editor decorations should also be responsive to theme changes
		this._commentThreadWidget.applyTheme(theme, fontInfo);
	}