fixed reverting a mixed-type polyadic sub-slot back to default

HISTORY.md

@@ -65,6 +65,7 @@
 * updated sw.js with new libraries
 * blocks, objects: added green flag symbol to "when I receive" dropdown menu
 * objects: support "when I receive" hat blocks with (empty) data when clicking the green flag button in the IDE
+* blocks: fixed reverting a mixed-type polyadic sub-slot back to default
 
 ### 2022-07-18
 * German translation update: Changed translation of "point in direction" to "setze Richtung auf ... Grad"

src/blocks.js

@@ -1395,7 +1395,7 @@ SyntaxElementMorph.prototype.revertToEmptyInput = function (arg) {
                 }
             }
         } else if (this instanceof MultiArgMorph) {
-            deflt = this.labelPart(this.slotSpec);
+            deflt = this.labelPart(this.slotSpecFor(inp));
         } else if (this instanceof ReporterSlotMorph) {
             deflt = this.emptySlot();
         }