diff --git a/history.txt b/history.txt
index 82652107..1a430fbc 100755
--- a/history.txt
+++ b/history.txt
@@ -2470,3 +2470,8 @@ ______
 150309
 ------
 * Blocks: fixed #738
+* GUI, Blocks: Only enable input caching for blocks
+
+150315
+------
+* Store: fixed #743
diff --git a/store.js b/store.js
index b17fb491..d4a2b641 100644
--- a/store.js
+++ b/store.js
@@ -61,7 +61,7 @@ SyntaxElementMorph, Variable*/
 
 // Global stuff ////////////////////////////////////////////////////////
 
-modules.store = '2015-February-28';
+modules.store = '2015-March-15';
 
 
 // XML_Serializer ///////////////////////////////////////////////////////
@@ -782,7 +782,7 @@ SnapSerializer.prototype.loadCustomBlocks = function (
 
         names = definition.parseSpec(definition.spec).filter(
             function (str) {
-                return str.charAt(0) === '%';
+                return str.charAt(0) === '%' && str.length > 1;
             }
         ).map(function (str) {
             return str.substr(1);