--- a/devtools/client/themes/dark-theme.css
+++ b/devtools/client/themes/dark-theme.css
@@ -163,17 +163,17 @@ body {
 .variable-or-property .token-domnode {
   font-weight: bold;
 }
 
 .theme-toolbar,
 .devtools-toolbar,
 .devtools-sidebar-tabs tabs,
 .devtools-sidebar-alltabs,
-.CodeMirror-dialog { /* General toolbar styling */
+.cm-s-mozilla .CodeMirror-dialog { /* General toolbar styling */
   color: var(--theme-body-color-alt);
   background-color: var(--theme-toolbar-background);
   border-color: hsla(210,8%,5%,.6);
 }
 
 .theme-fg-contrast { /* To be used for text on theme-bg-contrast */
   color: black;
 }

--- a/devtools/client/themes/light-theme.css
+++ b/devtools/client/themes/light-theme.css
@@ -166,17 +166,17 @@ body {
 .theme-fg-contrast { /* To be used for text on theme-bg-contrast */
   color: black;
 }
 
 .theme-toolbar,
 .devtools-toolbar,
 .devtools-sidebar-tabs tabs,
 .devtools-sidebar-alltabs,
-.CodeMirror-dialog { /* General toolbar styling */
+.cm-s-mozilla .CodeMirror-dialog { /* General toolbar styling */
   color: var(--theme-body-color-alt);
   background-color: var(--theme-toolbar-background);
   border-color: var(--theme-splitter-color);
 }
 
 .ruleview-swatch,
 .computedview-colorswatch {
   box-shadow: 0 0 0 1px #c4c4c4;