diff --git a/css/leptonChrome.css b/css/leptonChrome.css
index daf919e9..6b3670a1 100644
--- a/css/leptonChrome.css
+++ b/css/leptonChrome.css
@@ -8735,6 +8735,9 @@
   #sidebar {
     display: block;
   }
+  #main-window > body > box {
+    z-index: 2 !important;
+  }
 }
 @supports -moz-bool-pref("userChrome.sidebar.overlap") {
   #sidebar-box[positionend="true"] {
diff --git a/css/leptonChromeESR.css b/css/leptonChromeESR.css
index fb5a8a0d..15579c9c 100644
--- a/css/leptonChromeESR.css
+++ b/css/leptonChromeESR.css
@@ -9147,6 +9147,9 @@
   #sidebar {
     display: block;
   }
+  #main-window > body > box {
+    z-index: 2 !important;
+  }
 }
 @supports -moz-bool-pref("userChrome.sidebar.overlap") {
   #sidebar-box[positionend="true"] {
diff --git a/src/sidebar/_overlap.scss b/src/sidebar/_overlap.scss
index e318acb8..b1f15855 100644
--- a/src/sidebar/_overlap.scss
+++ b/src/sidebar/_overlap.scss
@@ -45,6 +45,11 @@
   #sidebar {
     display: block;
   }
+
+  // #navigator-toolbox-background
+  #main-window > body > box {
+    z-index: 2 !important;
+  }
 }
 
 @include Option("userChrome.sidebar.overlap") {