--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -2724,16 +2724,24 @@ Element::SetAttrAndNotify(int32_t aNames
       oldValue = nullptr;
     }
   } else {
     // No need to conditionally assign null here. If there was no previously
     // set value for the attribute, aOldValue will already be null.
     oldValue = aOldValue;
   }
 
+  if (aName == nsGkAtoms::hidden && HasAttr(kNameSpaceID_None, nsGkAtoms::hidden)) {
+    nsFocusManager *fm = nsFocusManager::GetFocusManager();
+
+    if (fm && fm->IsFocused(this)) {
+      fm->ClearFocus(OwnerDoc()->GetWindow());
+    }
+  }
+
   if (aComposedDocument || HasFlag(NODE_FORCE_XBL_BINDINGS)) {
     RefPtr<nsXBLBinding> binding = GetXBLBinding();
     if (binding) {
       binding->AttributeChanged(aName, aNamespaceID, false, aNotify);
     }
   }
 
   if (CustomElementRegistry::IsCustomElementEnabled()) {