diff --git a/core/renderers/block_rendering_rewrite/block_render_draw.js b/core/renderers/block_rendering_rewrite/block_render_draw.js
index 09c0ffedc..da58caae8 100644
--- a/core/renderers/block_rendering_rewrite/block_render_draw.js
+++ b/core/renderers/block_rendering_rewrite/block_render_draw.js
@@ -23,7 +23,7 @@
  * @author fenichel@google.com (Rachel Fenichel)
  */
 
-//'use strict';
+'use strict';
 goog.provide('Blockly.blockRendering.Drawer');
 
 goog.require('Blockly.blockRendering.constants');
diff --git a/core/renderers/block_rendering_rewrite/block_render_draw_debug.js b/core/renderers/block_rendering_rewrite/block_render_draw_debug.js
index 8446e7ed8..33869480e 100644
--- a/core/renderers/block_rendering_rewrite/block_render_draw_debug.js
+++ b/core/renderers/block_rendering_rewrite/block_render_draw_debug.js
@@ -23,7 +23,7 @@
  * @author fenichel@google.com (Rachel Fenichel)
  */
 
-//'use strict';
+'use strict';
 goog.provide('Blockly.blockRendering.Debug');
 goog.require('Blockly.blockRendering.RenderInfo');
 goog.require('Blockly.blockRendering.Highlighter');
diff --git a/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js b/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
index 0eae4f553..95d4f0615 100644
--- a/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
+++ b/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
@@ -23,7 +23,7 @@
  * @author fenichel@google.com (Rachel Fenichel)
  */
 
-//'use strict';
+'use strict';
 goog.provide('Blockly.blockRendering.Highlighter');
 
 goog.require('Blockly.blockRendering.constants');
diff --git a/core/renderers/block_rendering_rewrite/block_render_info.js b/core/renderers/block_rendering_rewrite/block_render_info.js
index b76bb6bb1..450479d6c 100644
--- a/core/renderers/block_rendering_rewrite/block_render_info.js
+++ b/core/renderers/block_rendering_rewrite/block_render_info.js
@@ -23,7 +23,7 @@
  * @author fenichel@google.com (Rachel Fenichel)
  */
 
-//'use strict';
+'use strict';
 
 goog.provide('Blockly.blockRendering.RenderInfo');