Fix group-only query bug and improve filtering consistency

addons/gecs/ecs/query_builder.gd

@@ -416,6 +416,25 @@ func matches(entities: Array) -> Array:
 					matches = false
 					break
 
+		# Check required groups
+		if matches and not _groups.is_empty():
+			for group in _groups:
+				if not entity.is_in_group(group):
+					matches = false
+					break
+
+		# Check excluded groups
+		if matches and not _exclude_groups.is_empty():
+			for group in _exclude_groups:
+				if entity.is_in_group(group):
+					matches = false
+					break
+
+		# Check enabled filter
+		if matches and _enabled_filter != null:
+			if entity.enabled != _enabled_filter:
+				matches = false
+
 		if matches:
 			result.append(entity)
 
@@ -453,6 +472,9 @@ func is_empty() -> bool:
 		and _exclude_components.is_empty()
 		and _relationships.is_empty()
 		and _exclude_relationships.is_empty()
+		and _groups.is_empty()
+		and _exclude_groups.is_empty()
+		and _enabled_filter == null
 	)
 
 

addons/gecs/ecs/system.gd

@@ -389,6 +389,8 @@ func _query_has_non_structural_filters(qb: QueryBuilder) -> bool:
 		return true
 	if not qb._exclude_groups.is_empty():
 		return true
+	if qb._enabled_filter != null:
+		return true
 	# Component property queries (ensure actual queries, not placeholders)
 	if not qb._all_components_queries.is_empty():
 		for query in qb._all_components_queries:
@@ -436,6 +438,9 @@ func _filter_entities_global(qb: QueryBuilder, entities: Array[Entity]) -> Array
 			for g in qb._exclude_groups:
 				if e.is_in_group(g):
 					include = false; break
+		if include and qb._enabled_filter != null:
+			if e.enabled != qb._enabled_filter:
+				include = false
 		if include and not qb._all_components_queries.is_empty():
 			for i in range(qb._all_components.size()):
 				if i >= qb._all_components_queries.size():