diff --git a/writeas/AppDelegate.swift b/writeas/AppDelegate.swift
index bc9c6b6..9b97019 100644
--- a/writeas/AppDelegate.swift
+++ b/writeas/AppDelegate.swift
@@ -20,12 +20,18 @@ class AppDelegate: NSObject, NSApplicationDelegate {
     @IBOutlet weak var formatFontSansItem: NSMenuItem!
     @IBOutlet weak var formatFontMonoItem: NSMenuItem!
 
+    struct GlobalSettings {
+        var isNight = false
+    }
+    var globalSettings = GlobalSettings()
+
     func applicationDidFinishLaunching(_ aNotification: Notification) {
         // Set night mode state
-        nightModeItem.state = Int(UserDefaults.standard.string(forKey: "night_mode_state") ?? String(NSOffState))!
-        if nightModeItem.state == NSOnState {
-            let wc = NSApplication.shared().mainWindow!.windowController as? WindowController
-            wc?.toggle(isNight: true)
+        let nightModeState = Int(UserDefaults.standard.string(forKey: "night_mode_state") ?? String(NSOffState))!
+        globalSettings.isNight = nightModeState == NSOnState
+        if globalSettings.isNight {
+            // Toggle Night Mode menu item on
+            toggleNightMode(nightModeItem)
         }
 
         // Set font
@@ -64,10 +70,14 @@ class AppDelegate: NSObject, NSApplicationDelegate {
     }
 
     @IBAction func toggleNightMode(_ sender: NSMenuItem) {
-        let wc = NSApplication.shared().mainWindow!.windowController as? WindowController
         let isOff = sender.state == NSOffState
-        wc?.toggle(isNight: isOff)
+
+        for w in NSApplication.shared().windows {
+            let wc = w.windowController as? WindowController
+            wc?.toggle(isNight: isOff)
+        }
         sender.state = isOff ? NSOnState : NSOffState
+        globalSettings.isNight = isOff
         UserDefaults.standard.set(String(sender.state), forKey: "night_mode_state")
     }
 
diff --git a/writeas/WindowController.swift b/writeas/WindowController.swift
index 18ec929..ee79ee5 100644
--- a/writeas/WindowController.swift
+++ b/writeas/WindowController.swift
@@ -18,6 +18,10 @@ class WindowController: NSWindowController {
         super.windowDidLoad()
 
         vc = (self.window?.contentViewController)! as! ViewController
+        let delegate = NSApplication.shared().delegate as! AppDelegate
+
+        // Set night mode state
+        vc?.toggle(isNight: delegate.globalSettings.isNight)
     }
 
     func toggle(isNight: Bool) {