diff --git a/assets/theme.css b/assets/theme.css
index 37eba06..1757f9b 100644
--- a/assets/theme.css
+++ b/assets/theme.css
@@ -5,11 +5,15 @@
 }
 */
 
-.toggle, .dialogButton, .titleBar, .windowIcon, .fileBarCloseButton,
+.toggle, .dialogButton, .titlebar, .titleBar, .windowIcon, .fileBarCloseButton,
 .newFileButton, .header, .paned, .panel, .tabs, .frame {
   all: unset;
 }
 
+windowcontrols {
+  all: unset;
+}
+
 .reorderable-page {
   all: unset;
 }
diff --git a/src/app/MetaBrush/Application/Action.hs b/src/app/MetaBrush/Application/Action.hs
index dd01901..206e041 100644
--- a/src/app/MetaBrush/Application/Action.hs
+++ b/src/app/MetaBrush/Application/Action.hs
@@ -426,7 +426,11 @@ instance HandleAction Close where
           | unsavedChanges documentContent
           -> do
             dialogWindow <- GTK.windowNew
-            GTK.setWindowDecorated dialogWindow False
+
+            -- Show a header, but not a "X" close button.
+            GTK.setWindowDecorated dialogWindow True
+            GTK.windowSetDeletable dialogWindow False
+            GTK.windowSetTitle dialogWindow ( Just "Warning" )
             GTK.windowSetTransientFor dialogWindow ( Just window )
 
             contentBox <- GTK.boxNew GTK.OrientationVertical 30
@@ -453,8 +457,8 @@ instance HandleAction Close where
             GTK.buttonSetLabel cancelButton "Cancel"
             GTK.boxAppend buttonBox cancelButton
 
-            widgetAddClasses dialogWindow ["metabrush", "bg", "plain", "text", "dialog"]
-            for_ [closeButton, saveCloseButton, cancelButton] \ button ->
+            widgetAddClasses dialogWindow [ "metabrush", "bg", "plain", "text", "dialog" ]
+            for_ [ closeButton, saveCloseButton, cancelButton ] \ button ->
               widgetAddClass button "dialogButton"
 
             void $ GTK.onButtonClicked closeButton $ do