src/vs/editor/contrib/gotoError/gotoErrorWidget.ts/MarkerNavigationWidget/_applyTheme
class MarkerNavigationWidget:	private _applyTheme(theme: IColorTheme) {
		this._backgroundColor = theme.getColor(editorMarkerNavigationBackground);
		let colorId = editorMarkerNavigationError;
		if (this._severity === MarkerSeverity.Warning) {
			colorId = editorMarkerNavigationWarning;
		} else if (this._severity === MarkerSeverity.Info) {
			colorId = editorMarkerNavigationInfo;
		}
		const frameColor = theme.getColor(colorId);
		this.style({
			arrowColor: frameColor,
			frameColor: frameColor,
			headerBackgroundColor: this._backgroundColor,
			primaryHeadingColor: theme.getColor(peekViewTitleForeground),
			secondaryHeadingColor: theme.getColor(peekViewTitleInfoForeground)
		}); // style() will trigger _applyStyles
	}