diff --git a/Compatibility-Issues-Solution.md b/Compatibility-Issues-Solution.md
index 0470ef3..bffd3b8 100644
--- a/Compatibility-Issues-Solution.md
+++ b/Compatibility-Issues-Solution.md
@@ -55,4 +55,15 @@ Add this code [#28](https://github.com/black7375/Firefox-UI-Fix/issues/28) [#40]
   :root #appMenu-popup panelview {
     width: 25em !important; /* can modify panel width, Original: 22.5em */
   }
+```
+
+## White outline on the top of address bar
+
+![image](https://user-images.githubusercontent.com/25581533/124436944-10038180-dd66-11eb-8933-c285a7b7e5c7.png)
+
+Add this code [#99](https://github.com/black7375/Firefox-UI-Fix/issues/99)
+```css
+  #nav-bar {
+    box-shadow: none !important;
+  }
 ```
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