diff --git a/services/web/frontend/js/features/source-editor/lezer-latex/latex.grammar b/services/web/frontend/js/features/source-editor/lezer-latex/latex.grammar
index 82efa49c4a..84e7c4fa3a 100644
--- a/services/web/frontend/js/features/source-editor/lezer-latex/latex.grammar
+++ b/services/web/frontend/js/features/source-editor/lezer-latex/latex.grammar
@@ -521,7 +521,7 @@ DefinitionFragmentArgument {
 
 DefinitionFragmentCommand {
       KnownCommand<TextArgument>
-    | UnknownCommand { genericUnknownCommandWithOptionalArguments<DefinitionFragmentArgument, OptionalArgument> }
+    | DefinitionFragmentUnknownCommand { genericUnknownCommandWithOptionalArguments<DefinitionFragmentArgument, OptionalArgument> }
     | KnownCtrlSym
 }
 
diff --git a/services/web/frontend/js/features/source-editor/utils/tree-operations/commands.ts b/services/web/frontend/js/features/source-editor/utils/tree-operations/commands.ts
index ccec68aca9..9cdab1ee75 100644
--- a/services/web/frontend/js/features/source-editor/utils/tree-operations/commands.ts
+++ b/services/web/frontend/js/features/source-editor/utils/tree-operations/commands.ts
@@ -75,7 +75,8 @@ export const enterNode = (
   } else if (
     node.type.is('UnknownCommand') ||
     node.type.is('KnownCommand') ||
-    node.type.is('MathUnknownCommand')
+    node.type.is('MathUnknownCommand') ||
+    node.type.is('DefinitionFragmentUnknownCommand')
   ) {
     let commandNode: SyntaxNode | null = node.node
     if (node.type.is('KnownCommand')) {