Fix advanced icons

theme/blockly.less

@@ -120,6 +120,10 @@ span.blocklyTreeIcon.blocklyTreeIconadvancedcollapsed::before {
     content: "\f116";
 }
 
+span.blocklyTreeIcon.blocklyTreeIconadvancedexpanded::before {
+    content: "\f117";
+}
+
 .save-editortools-btn .icon.save::before {
     content: "\f115"
 }