diff --git a/web/third/bootstrap/css/bootstrap.app.css b/web/third/bootstrap/css/bootstrap.app.css
index 4654f57661..2b22f4f5b3 100644
--- a/web/third/bootstrap/css/bootstrap.app.css
+++ b/web/third/bootstrap/css/bootstrap.app.css
@@ -430,14 +430,6 @@ input:focus:invalid:focus {
 .open > .dropdown-menu {
   display: block;
 }
-.dropdown-backdrop {
-  position: fixed;
-  left: 0;
-  right: 0;
-  bottom: 0;
-  top: 0;
-  z-index: 990;
-}
 .typeahead {
   z-index: 1051;
   margin-top: 2px;
diff --git a/web/third/bootstrap/css/bootstrap.portico.css b/web/third/bootstrap/css/bootstrap.portico.css
index 442ae1f22d..c58c8cdefa 100644
--- a/web/third/bootstrap/css/bootstrap.portico.css
+++ b/web/third/bootstrap/css/bootstrap.portico.css
@@ -427,14 +427,6 @@ input:focus:invalid:focus {
 .open > .dropdown-menu {
   display: block;
 }
-.dropdown-backdrop {
-  position: fixed;
-  left: 0;
-  right: 0;
-  bottom: 0;
-  top: 0;
-  z-index: 990;
-}
 .typeahead {
   z-index: 1051;
   margin-top: 2px;