diff --git a/layout/html/document/src/ua.css b/layout/html/document/src/ua.css
index 3b56528c69c..f882ee32c8d 100644
--- a/layout/html/document/src/ua.css
+++ b/layout/html/document/src/ua.css
@@ -299,6 +299,15 @@ DD {
 
 // Leafs
 
+APPLET {
+  display: inline;
+}
+EMBED {
+  display: inline;
+}
+OBJECT {
+  display: inline;
+}
 HR {
   display: block;
 }
diff --git a/layout/style/ua.css b/layout/style/ua.css
index 3b56528c69c..f882ee32c8d 100644
--- a/layout/style/ua.css
+++ b/layout/style/ua.css
@@ -299,6 +299,15 @@ DD {
 
 // Leafs
 
+APPLET {
+  display: inline;
+}
+EMBED {
+  display: inline;
+}
+OBJECT {
+  display: inline;
+}
 HR {
   display: block;
 }