diff --git a/src/mol-plugin/state/animation/built-in.ts b/src/mol-plugin/state/animation/built-in.ts
index d22b1bf84be7ee3c408b24434026ea5a31cbde9f..86593b3f48b0e62aabbb14236eef4d158aca02e0 100644
--- a/src/mol-plugin/state/animation/built-in.ts
+++ b/src/mol-plugin/state/animation/built-in.ts
@@ -16,7 +16,7 @@ export const AnimateModelIndex = PluginStateAnimation.create({
     display: { name: 'Animate Model Index' },
     params: () => ({
         mode: PD.MappedStatic('once', {
-            once: PD.Group({ direction: PD.Select('forward', [['forward', 'Forward'], ['backward', 'Backward']]) }),
+            once: PD.Group({ direction: PD.Select('forward', [['forward', 'Forward'], ['backward', 'Backward']]) }, { isFlat: true }),
             palindrome: PD.Group({ }),
             loop: PD.Group({ }),
         }, { options: [['once', 'Once'], ['palindrome', 'Palindrome'], ['loop', 'Loop']] }),
diff --git a/src/mol-plugin/ui/controls/parameters.tsx b/src/mol-plugin/ui/controls/parameters.tsx
index 03a22c1ab5aeb86e4f1b780d454dcfdc06d1ff36..868c44f16e20e6ae927fe732b197831b73504546 100644
--- a/src/mol-plugin/ui/controls/parameters.tsx
+++ b/src/mol-plugin/ui/controls/parameters.tsx
@@ -436,6 +436,10 @@ export class GroupControl extends React.PureComponent<ParamProps<PD.Group<any>>,
 
     render() {
         const params = this.props.param.params;
+
+        // Do not show if there are no params.
+        if (Object.keys(params).length === 0) return null;
+
         const label = this.props.param.label || camelCaseToWords(this.props.name);
 
         const controls = <ParameterControls params={params} onChange={this.onChangeParam} values={this.props.value} onEnter={this.props.onEnter} isDisabled={this.props.isDisabled} />;