src/vs/workbench/contrib/debug/browser/callStackView.ts/CallStackCompressionDelegate/isIncompressible
class CallStackCompressionDelegate:	isIncompressible(stat: CallStackItem): boolean {
		if (isDebugSession(stat)) {
			if (stat.compact) {
				return false;
			}
			const sessions = this.debugService.getModel().getSessions();
			if (sessions.some(s => s.parentSession === stat && s.compact)) {
				return false;
			}

			return true;
		}

		return true;
	}