diff --git a/toonz/sources/toonz/subscenecommand.cpp b/toonz/sources/toonz/subscenecommand.cpp
index 1df1c505..f683c6d1 100644
--- a/toonz/sources/toonz/subscenecommand.cpp
+++ b/toonz/sources/toonz/subscenecommand.cpp
@@ -973,7 +973,8 @@ std::set<int> explode(TXsheet *xsh, TXsheet *subXsh, int index,
 
   QMap<TFx *, TFx *> fxMap;
   for (auto it = fxs.constBegin(); it != fxs.constEnd(); ++it) {
-    setGrammerToParams(it.value().first->getParams(), grammer);
+    if (it.value().first)
+      setGrammerToParams(it.value().first->getParams(), grammer);
     fxMap.insert(it.key(), it.value().first);
   }