diff --git a/mail/themes/linux/mail/messenger.css b/mail/themes/linux/mail/messenger.css
index 1acee75243..c8578e55f7 100644
--- a/mail/themes/linux/mail/messenger.css
+++ b/mail/themes/linux/mail/messenger.css
@@ -231,6 +231,11 @@ toolbar:not(.inline-toolbar):not(:-moz-lwtheme)
   height: 18px;
 }
 
+.toolbarbutton-1[disabled=true]:-moz-lwtheme,
+.toolbarbutton-menubutton-button[disabled=true]:-moz-lwtheme {
+  color: inherit;
+}
+
 toolbar[mode="full"] .toolbarbutton-1 {
   min-width: 55px;
 }
diff --git a/mail/themes/osx/mail/messenger.css b/mail/themes/osx/mail/messenger.css
index 568008aee1..cadd265eb4 100644
--- a/mail/themes/osx/mail/messenger.css
+++ b/mail/themes/osx/mail/messenger.css
@@ -203,6 +203,11 @@ toolbar:not([mode="icons"]) .toolbarbutton-1 > .toolbarbutton-menubutton-button
   height: 18px;
 }
 
+.toolbarbutton-1[disabled=true]:-moz-lwtheme,
+.toolbarbutton-menubutton-button[disabled=true]:-moz-lwtheme {
+  color: inherit !important;
+}
+
 .toolbarbutton-1[disabled="true"] .toolbarbutton-text,
 .toolbarbutton-1[disabled="true"] .toolbarbutton-icon,
 .toolbarbutton-1[type="menu-button"] > .toolbarbutton-menubutton-button[disabled="true"]
diff --git a/mail/themes/windows/mail/messenger.css b/mail/themes/windows/mail/messenger.css
index 4927f2079d..787882c5a1 100644
--- a/mail/themes/windows/mail/messenger.css
+++ b/mail/themes/windows/mail/messenger.css
@@ -77,6 +77,16 @@ toolbox[labelalign="end"] .toolbarbutton-1[type="menu-button"]
   padding: 1px 5px !important;
 }
 
+.toolbarbutton-1[disabled=true]:-moz-lwtheme,
+.toolbarbutton-menubutton-button[disabled=true]:-moz-lwtheme {
+  color: inherit;
+  text-shadow: inherit;
+}
+
+.toolbarbutton-1[disabled=true]:-moz-lwtheme .toolbarbutton-text {
+  opacity: .4;
+}
+
 toolbox[labelalign="end"] > toolbar[mode="full"] .toolbarbutton-1 .toolbarbutton-text {
   padding-inline-start: 2px;
 }