diff --git a/sale_cost.py b/sale_cost.py
index 2a3a21f..d391ec4 100644
--- a/sale_cost.py
+++ b/sale_cost.py
@@ -54,3 +54,7 @@ class SaleCost(ApplyMethodCostDocumentMixin, metaclass=PoolMeta):
             invisible_condition,
             Not(Bool(Eval('invoice_lines'))))
         cls._buttons['unapply']['depends'].append('invoice_lines')
+
+    @property
+    def non_explodable(self):
+        return super().non_explodable or bool(self.invoice_lines)