diff --git a/core/generator.js b/core/generator.js
index fecc35531..20fb77565 100644
--- a/core/generator.js
+++ b/core/generator.js
@@ -187,8 +187,9 @@ Blockly.Generator.prototype.blockToCode = function(block) {
         'Expecting string from statement block "%s".', block.type);
     return [this.scrub_(block, code[0]), code[1]];
   } else if (goog.isString(code)) {
+    var id = block.id.replace(/\$/g, '$$$$');  // Issue 251.
     if (this.STATEMENT_PREFIX) {
-      code = this.STATEMENT_PREFIX.replace(/%1/g, '\'' + block.id + '\'') +
+      code = this.STATEMENT_PREFIX.replace(/%1/g, '\'' + id + '\'') +
           code;
     }
     return this.scrub_(block, code);
@@ -297,6 +298,7 @@ Blockly.Generator.prototype.statementToCode = function(block, name) {
  * @return {string} Loop contents, with infinite loop trap added.
  */
 Blockly.Generator.prototype.addLoopTrap = function(branch, id) {
+  id = id.replace(/\$/g, '$$$$');  // Issue 251.
   if (this.INFINITE_LOOP_TRAP) {
     branch = this.INFINITE_LOOP_TRAP.replace(/%1/g, '\'' + id + '\'') + branch;
   }
diff --git a/core/utils.js b/core/utils.js
index 35a10ea58..8d87cdc4d 100644
--- a/core/utils.js
+++ b/core/utils.js
@@ -543,12 +543,13 @@ Blockly.genUid = function() {
 };
 
 /**
- * Legal characters for the unique ID.
- * Should be all on a US keyboard.  No XML special characters or control codes.
- * Removed $ due to issue 251.
+ * Legal characters for the unique ID.  Should be all on a US keyboard.
+ * No characters that conflict with XML or JSON.  Requests to remove additional
+ * 'problematic' characters from this soup will be denied.  That's your failure
+ * to properly escape in your own environment.  Issues #251, #625, #682.
  * @private
  */
-Blockly.genUid.soup_ = '!#%()*+,-./:;=?@[]^_`{|}~' +
+Blockly.genUid.soup_ = '!#$%()*+,-./:;=?@[]^_`{|}~' +
     'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
 
 /**
diff --git a/core/workspace_svg.js b/core/workspace_svg.js
index 4a9737c37..313308d11 100644
--- a/core/workspace_svg.js
+++ b/core/workspace_svg.js
@@ -1305,7 +1305,8 @@ Blockly.WorkspaceSvg.prototype.updateGridPattern_ = function() {
  * .flyoutWidth: Width of the flyout if it is always open.  Otherwise zero.
  * .flyoutHeight: Height of flyout if it is always open.  Otherwise zero.
  * .toolboxPosition: Top, bottom, left or right.
- * @return {Object} Contains size and position metrics of a top level workspace.
+ * @return {!Object} Contains size and position metrics of a top level
+ *   workspace.
  * @private
  * @this Blockly.WorkspaceSvg
  */
diff --git a/tests/generators/unittest.js b/tests/generators/unittest.js
index d2b94e66d..5c471d1b7 100644
--- a/tests/generators/unittest.js
+++ b/tests/generators/unittest.js
@@ -111,7 +111,7 @@ Blockly.Blocks['unittest_adjustindex'] = {
       "output": "Number",
       "colour": 65,
       "tooltip": "Adjusts the value based on whether generated code is using " +
-          "zero or one based indexing"
+          "zero or one based indexing."
     });
   }
 };