src/vs/workbench/contrib/terminal/browser/xterm/decorationAddon.ts/DecorationAddon/registerMarkDecoration
class DecorationAddon:	registerMarkDecoration(mark: IMarkProperties): IDecoration | undefined {
		if (!this._terminal || (!this._showGutterDecorations && !this._showOverviewRulerDecorations)) {
			return undefined;
		}
		if (mark.hidden) {
			return undefined;
		}
		return this.registerCommandDecoration(undefined, undefined, mark);
	}