diff --git a/src/insets/InsetBox.cpp b/src/insets/InsetBox.cpp
index eee16fe647..ea18afa0d9 100644
--- a/src/insets/InsetBox.cpp
+++ b/src/insets/InsetBox.cpp
@@ -169,7 +169,7 @@ void InsetBox::setButtonLabel()
 
 bool InsetBox::hasFixedWidth() const
 {
-	return !params_.width.empty();
+	return !params_.width.empty() && params_.special == "none";
 }