diff --git a/resources/celerity/map.php b/resources/celerity/map.php
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -121,7 +121,7 @@
     'rsrc/css/fuel/fuel-handle-list.css' => '2c4cbeca',
     'rsrc/css/fuel/fuel-map.css' => 'd6e31510',
     'rsrc/css/fuel/fuel-menu.css' => '21f5d199',
-    'rsrc/css/layout/phabricator-source-code-view.css' => '03d7ac28',
+    'rsrc/css/layout/phabricator-source-code-view.css' => '6b31244f',
     'rsrc/css/phui/button/phui-button-bar.css' => 'a4aa75c4',
     'rsrc/css/phui/button/phui-button-simple.css' => '1ff278aa',
     'rsrc/css/phui/button/phui-button.css' => 'ea704902',
@@ -803,7 +803,7 @@
     'phabricator-search-results-css' => '9ea70ace',
     'phabricator-shaped-request' => '995f5102',
     'phabricator-slowvote-css' => '1694baed',
-    'phabricator-source-code-view-css' => '03d7ac28',
+    'phabricator-source-code-view-css' => '6b31244f',
     'phabricator-standard-page-view' => 'a374f94c',
     'phabricator-textareautils' => 'f340a484',
     'phabricator-title' => '43bc9360',
diff --git a/webroot/rsrc/css/layout/phabricator-source-code-view.css b/webroot/rsrc/css/layout/phabricator-source-code-view.css
--- a/webroot/rsrc/css/layout/phabricator-source-code-view.css
+++ b/webroot/rsrc/css/layout/phabricator-source-code-view.css
@@ -25,6 +25,8 @@
   border-right: 1px solid {$paste.border};
   color: {$sh-yellowtext};
   white-space: nowrap;
+  -webkit-user-select: none;
+  user-select: none;
 }
 
 .phabricator-source-line > a::before {