--- a/devtools/client/themes/common.css
+++ b/devtools/client/themes/common.css
@@ -489,17 +489,19 @@ checkbox:-moz-focusring {
   outline: none;
 }
 
 .devtools-searchbox .devtools-autocomplete-popup {
   position: absolute;
   top: 100%;
   width: 100%;
   line-height: initial !important;
-  z-index: 999;
+  /* See bug - 1414609. z-index is greater than 1000 so that searchbox's z-index
+  is more than z-index of requests-list-headers-wrapper in netmonitor */
+  z-index: 1001;
 }
 
 /* Don't add 'double spacing' for inputs that are at beginning / end
    of a toolbar (since the toolbar has it's own spacing). */
 .devtools-toolbar > .devtools-textinput:first-child,
 .devtools-toolbar > .devtools-searchinput:first-child,
 .devtools-toolbar > .devtools-filterinput:first-child {
   margin-inline-start: 0;