diff --git a/src/mol-plugin-ui/controls/parameters.tsx b/src/mol-plugin-ui/controls/parameters.tsx
index bb145adaa95e304a0faf19bb747bcf07a7f2b8ff..4501a36c2b614a43d0d9ed194546c92a72947c51 100644
--- a/src/mol-plugin-ui/controls/parameters.tsx
+++ b/src/mol-plugin-ui/controls/parameters.tsx
@@ -55,7 +55,7 @@ export class ParameterControls<P extends PD.Params> extends React.PureComponent<
         if (!ctrls) return null;
 
         if (category) {
-            return [<ExpandGroup header={category}>{ctrls}</ExpandGroup>];
+            return [<ExpandGroup key={category} header={category}>{ctrls}</ExpandGroup>];
         }
         return ctrls;
     }