diff --git a/resources/qml/SidebarSimple.qml b/resources/qml/SidebarSimple.qml
index 0e1b04cdeb..a45037ff56 100644
--- a/resources/qml/SidebarSimple.qml
+++ b/resources/qml/SidebarSimple.qml
@@ -327,7 +327,8 @@ Item
                     supportEnabled.setPropertyValue("value", false);
                 } else {
                     supportEnabled.setPropertyValue("value", true);
-                    supportExtruderNr.setPropertyValue("value", index - 1);
+                    // Send the extruder nr as a string.
+                    supportExtruderNr.setPropertyValue("value", parseInt(index - 1) + "");
                 }
             }
             MouseArea {