diff --git a/properties_pane/entity_level/entityLevelConfig.json b/properties_pane/entity_level/entityLevelConfig.json
index 42a7185..213aaca 100644
--- a/properties_pane/entity_level/entityLevelConfig.json
+++ b/properties_pane/entity_level/entityLevelConfig.json
@@ -1646,7 +1646,10 @@ making sure that you maintain a proper JSON format.
 						"propertyTooltip": "Expression",
 						"propertyType": "details",
 						"template": "textarea",
-						"markdown": false
+						"markdown": false,
+						"validation": {
+							"required": true
+						}
 					},
 					{
 						"propertyName": "No inherit",