diff --git a/src/infrastructure/markup/rule/PhabricatorKeyboardRemarkupRule.php b/src/infrastructure/markup/rule/PhabricatorKeyboardRemarkupRule.php
--- a/src/infrastructure/markup/rule/PhabricatorKeyboardRemarkupRule.php
+++ b/src/infrastructure/markup/rule/PhabricatorKeyboardRemarkupRule.php
@@ -212,6 +212,7 @@
         'line-height: 0.6rem;',
         'border-radius: 3px;',
         'box-shadow: inset 0 -1px 0 rgba(71, 87, 120, 0.08);',
+        '-webkit-user-select: none;',
         'user-select: none;',
         'background: #f7f7f7;',
         'border: 1px solid #C7CCD9;',
diff --git a/webroot/rsrc/css/application/base/standard-page-view.css b/webroot/rsrc/css/application/base/standard-page-view.css
--- a/webroot/rsrc/css/application/base/standard-page-view.css
+++ b/webroot/rsrc/css/application/base/standard-page-view.css
@@ -74,6 +74,7 @@
   text-decoration: none;
   border-radius: 3px;
   box-shadow: inset 0 -1px 0 rgba({$alphablue}, 0.08);
+  -webkit-user-select: none;
   user-select: none;
   color: {$darkgreytext};
   background: {$lightgreybackground};
diff --git a/webroot/rsrc/css/application/differential/changeset-view.css b/webroot/rsrc/css/application/differential/changeset-view.css
--- a/webroot/rsrc/css/application/differential/changeset-view.css
+++ b/webroot/rsrc/css/application/differential/changeset-view.css
@@ -432,37 +432,27 @@
 
 .differential-diff.copy-l > tbody > tr > td,
 .differential-diff.copy-r > tbody > tr > td {
-  -moz-user-select: none;
-  -ms-user-select: none;
   -webkit-user-select: none;
   user-select: none;
 }
 
 .differential-diff.copy-l > tbody > tr > td:nth-child(2) {
-  -moz-user-select: auto;
-  -ms-user-select: auto;
   -webkit-user-select: auto;
   user-select: auto;
 }
 
 .differential-diff.copy-l > tbody > tr > td.show-more:nth-child(2) {
-  -moz-user-select: none;
-  -ms-user-select: none;
   -webkit-user-select: none;
   user-select: none;
 }
 
 .differential-diff.copy-r > tbody > tr > td:nth-child(5) {
-  -moz-user-select: auto;
-  -ms-user-select: auto;
   -webkit-user-select: auto;
   user-select: auto;
 }
 
 .differential-diff.copy-l > tbody > tr.inline > td,
 .differential-diff.copy-r > tbody > tr.inline > td {
-  -moz-user-select: none;
-  -ms-user-select: none;
   -webkit-user-select: none;
   user-select: none;
 }
diff --git a/webroot/rsrc/css/application/harbormaster/harbormaster.css b/webroot/rsrc/css/application/harbormaster/harbormaster.css
--- a/webroot/rsrc/css/application/harbormaster/harbormaster.css
+++ b/webroot/rsrc/css/application/harbormaster/harbormaster.css
@@ -44,10 +44,7 @@
   background-color: {$paste.highlight};
   border-right: 1px solid {$paste.border};
 
-  -moz-user-select: -moz-none;
-  -khtml-user-select: none;
   -webkit-user-select: none;
-  -ms-user-select: none;
   user-select: none;
 }
 
diff --git a/webroot/rsrc/css/core/remarkup.css b/webroot/rsrc/css/core/remarkup.css
--- a/webroot/rsrc/css/core/remarkup.css
+++ b/webroot/rsrc/css/core/remarkup.css
@@ -66,6 +66,7 @@
   line-height: 0.6rem;
   border-radius: 3px;
   box-shadow: inset 0 -1px 0 rgba({$alphablue},0.08);
+  -webkit-user-select: none;
   user-select: none;
   background: {$lightgreybackground};
   border: 1px solid {$lightgreyborder};
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
@@ -74,10 +74,7 @@
 
 .phabricator-source-blame-skip,
 .phabricator-source-blame-info {
-  -moz-user-select: -moz-none;
-  -khtml-user-select: none;
   -webkit-user-select: none;
-  -ms-user-select: none;
   user-select: none;
 }
 
diff --git a/webroot/rsrc/css/phui/button/phui-button.css b/webroot/rsrc/css/phui/button/phui-button.css
--- a/webroot/rsrc/css/phui/button/phui-button.css
+++ b/webroot/rsrc/css/phui/button/phui-button.css
@@ -9,8 +9,6 @@
   font: {$basefont};
   -webkit-font-smoothing: antialiased;
   -webkit-user-select: none;
-  -moz-user-select: none;
-  -ms-user-select: none;
   user-select: none;
 }
 
diff --git a/webroot/rsrc/css/phui/object-item/phui-oi-list-view.css b/webroot/rsrc/css/phui/object-item/phui-oi-list-view.css
--- a/webroot/rsrc/css/phui/object-item/phui-oi-list-view.css
+++ b/webroot/rsrc/css/phui/object-item/phui-oi-list-view.css
@@ -675,8 +675,8 @@
 
 .phui-oi-selectable {
   cursor: pointer;
-  user-select: none;
   -webkit-user-select: none;
+  user-select: none;
 }
 
 /* When the list selection state can be toggled on the client (as in the bulk
diff --git a/webroot/rsrc/css/phui/workboards/phui-workcard.css b/webroot/rsrc/css/phui/workboards/phui-workcard.css
--- a/webroot/rsrc/css/phui/workboards/phui-workcard.css
+++ b/webroot/rsrc/css/phui/workboards/phui-workcard.css
@@ -28,9 +28,6 @@
 .phui-workcard.phui-oi .phui-oi-objname {
   -webkit-touch-callout: text;
   -webkit-user-select: text;
-  -khtml-user-select: text;
-  -moz-user-select: text;
-  -ms-user-select: text;
   user-select: text;
 }
 
diff --git a/webroot/rsrc/css/phui/workboards/phui-workpanel.css b/webroot/rsrc/css/phui/workboards/phui-workpanel.css
--- a/webroot/rsrc/css/phui/workboards/phui-workpanel.css
+++ b/webroot/rsrc/css/phui/workboards/phui-workpanel.css
@@ -29,9 +29,6 @@
 .phui-workboard-view {
   -webkit-touch-callout: none;
   -webkit-user-select: none;
-  -khtml-user-select: none;
-  -moz-user-select: none;
-  -ms-user-select: none;
   user-select: none;
 }