diff --git a/browser/themes/linux/preferences/applications.css b/browser/themes/linux/preferences/applications.css
index fd4d001e09bc..e87d86ac50d4 100644
--- a/browser/themes/linux/preferences/applications.css
+++ b/browser/themes/linux/preferences/applications.css
@@ -9,16 +9,13 @@
  * Also make sure the labels are the same distance away from the icons.
  */
 .actionsMenu {
-  margin-top: -1px;
-  margin-bottom: -1px;
-  margin-inline-start: -1px;
-  margin-inline-end: 0;
+  margin-block: -1px;
+  margin-inline: -1px 0;
 }
 
 .typeIcon,
 .actionIcon {
-  margin-inline-start: 3px;
-  margin-inline-end: 3px;
+  margin-inline: 3px;
 }
 
 #handlersView > richlistitem label {
@@ -46,7 +43,7 @@ menuitem[appHandlerIcon="plugin"] {
 }
 
 .actionsMenu .menulist-icon {
-  margin-inline-end: 1px;
+  margin-inline: 1px 8px;
   height: 16px;
   width: 16px;
 }
diff --git a/browser/themes/linux/preferences/in-content/preferences.css b/browser/themes/linux/preferences/in-content/preferences.css
index 4380f9376f57..adc15a0094fb 100644
--- a/browser/themes/linux/preferences/in-content/preferences.css
+++ b/browser/themes/linux/preferences/in-content/preferences.css
@@ -12,7 +12,3 @@ body {
   /* override the Linux only toolkit rule */
   -moz-appearance: none;
 }
-
-.actionsMenu > .menulist-label-box > .menulist-icon {
-  margin-inline: 1px 8px;
-}
diff --git a/browser/themes/osx/preferences/applications.css b/browser/themes/osx/preferences/applications.css
index 85855d338236..52063dc2c33d 100644
--- a/browser/themes/osx/preferences/applications.css
+++ b/browser/themes/osx/preferences/applications.css
@@ -10,8 +10,12 @@
  */
 .actionsMenu {
   margin-inline-start: -2px;
-  margin-top: 0;
-  margin-bottom: -1px;
+  margin-block: 0 -1px;
+}
+
+.typeIcon,
+.actionIcon {
+  margin-inline: 3px 2px;
 }
 
 #handlersView > richlistitem label {
@@ -23,19 +27,18 @@
   min-height: 22px;
 }
 
-.typeIcon,
-.actionIcon {
-  margin-inline-start: 3px;
-}
-
 .typeIcon,
 .actionIcon,
 .actionsMenu .menulist-icon {
-  margin-inline-end: 2px;
   height: 16px;
   width: 16px;
 }
 
+.actionsMenu .menulist-icon {
+  margin-top: 2px;
+  margin-inline: 2px 8px;
+}
+
 .actionsMenu > menupopup > menuitem > .menu-iconic-left {
   /* Undo content/browser/preferences/handlers.css - we don't
    * want icon-less labels to line up with the other labels.
diff --git a/browser/themes/osx/preferences/in-content/preferences.css b/browser/themes/osx/preferences/in-content/preferences.css
index c33f8d55e319..b07ffed57e07 100644
--- a/browser/themes/osx/preferences/in-content/preferences.css
+++ b/browser/themes/osx/preferences/in-content/preferences.css
@@ -8,12 +8,6 @@ body {
   font-size: 1.36em;
 }
 
-.actionsMenu > .menulist-label-box > .menulist-icon {
-  margin-top: 2px;
-  margin-inline-start: 2px;
-  margin-inline-end: 8px !important;
-}
-
 #popupPolicyRow {
   /* Override styles from
      browser/themes/osx/preferences/preferences.css */
diff --git a/browser/themes/windows/preferences/applications.css b/browser/themes/windows/preferences/applications.css
index d18f613d4973..45c927215873 100644
--- a/browser/themes/windows/preferences/applications.css
+++ b/browser/themes/windows/preferences/applications.css
@@ -9,16 +9,13 @@
  * Also make sure the labels are the same distance away from the icons.
  */
 .actionsMenu {
-  margin-top: 0;
-  margin-bottom: 0;
-  margin-inline-start: -2px;
-  margin-inline-end: 0;
+  margin-block: 0;
+  margin-inline: -2px 0;
 }
 
 .typeIcon,
 .actionIcon {
-  margin-inline-start: 3px;
-  margin-inline-end: 3px;
+  margin-inline: 3px;
 }
 
 #handlersView > richlistitem label {
@@ -46,7 +43,7 @@ menuitem[appHandlerIcon="plugin"] {
 }
 
 .actionsMenu .menulist-icon {
-  margin-inline-end: 3px;
+  margin-inline-end: 9px;
   height: 16px;
   width: 16px;
 }
diff --git a/browser/themes/windows/preferences/in-content-new/preferences.css b/browser/themes/windows/preferences/in-content-new/preferences.css
deleted file mode 100644
index 8d7d44d2d333..000000000000
--- a/browser/themes/windows/preferences/in-content-new/preferences.css
+++ /dev/null
@@ -1,9 +0,0 @@
-/* - This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this file,
-   - You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-%include ../../../shared/incontentprefs/preferences.inc.css
-
-.actionsMenu > .menulist-label-box > .menulist-icon {
-  margin-inline-end: 9px;
-}
diff --git a/browser/themes/windows/preferences/in-content/preferences.css b/browser/themes/windows/preferences/in-content/preferences.css
index a24a833ba894..aedf6a312a64 100644
--- a/browser/themes/windows/preferences/in-content/preferences.css
+++ b/browser/themes/windows/preferences/in-content/preferences.css
@@ -7,7 +7,3 @@
 body {
   font-size: 1.25em;
 }
-
-.actionsMenu > .menulist-label-box > .menulist-icon {
-  margin-inline-end: 9px;
-}