diff --git a/pxtcompiler/emitter/decompiler.ts b/pxtcompiler/emitter/decompiler.ts
index 1db0f7340b19..b955f7a9b52c 100644
--- a/pxtcompiler/emitter/decompiler.ts
+++ b/pxtcompiler/emitter/decompiler.ts
@@ -1193,7 +1193,7 @@ ${output}</xml>`;
                 return r;
             }
 
-            let value = U.htmlEscape(attributes.blockId || callInfo.qName);
+            let value = U.htmlEscape(attributes.blockId) || callInfo.qName;
 
             const [parent,] = getParent(n);
             const parentCallInfo: pxtc.CallInfo = parent && pxtInfo(parent).callInfo;
diff --git a/pxtlib/service.ts b/pxtlib/service.ts
index 2e67d440482f..d630f5fd8f15 100644
--- a/pxtlib/service.ts
+++ b/pxtlib/service.ts
@@ -592,7 +592,8 @@ namespace ts.pxtc {
                 && s.kind != pxtc.SymbolKind.EnumMember
                 && s.kind != pxtc.SymbolKind.Module
                 && s.kind != pxtc.SymbolKind.Interface
-                && s.kind != pxtc.SymbolKind.Class) {
+                && s.kind != pxtc.SymbolKind.Class
+                && !s.attributes.blockIdentity) {
                 if (!s.attributes.blockId)
                     s.attributes.blockId = s.qName.replace(/\./g, "_")
                 if (s.attributes.block == "true") {