diff --git a/src/ui/generic-components/TrafficLightButton.swift b/src/ui/generic-components/TrafficLightButton.swift
index 82170afd..4721ff62 100644
--- a/src/ui/generic-components/TrafficLightButton.swift
+++ b/src/ui/generic-components/TrafficLightButton.swift
@@ -118,32 +118,48 @@ class TrafficLightButton: NSButton {
     }
 
     private func drawSymbol(_ lineColor: NSColor) {
+        let symbol = NSBezierPath()
         if (type == .fullscreen) {
-            let symbol = NSBezierPath()
-            symbol.move(to: NSMakePoint(bounds.width * 0.25, bounds.height * 0.75))
-            symbol.line(to: NSMakePoint(bounds.width * 0.25, bounds.height * 1 / 3))
-            symbol.line(to: NSMakePoint(bounds.width * 2 / 3, bounds.height * 0.75))
+            var firstPointA, firstPointB, firstPointC, secondPointA, secondPointB, secondPointC: NSPoint!
+            if window_?.isFullscreen ?? false {
+                // Defullscreen symbol that the angles of the two triangles are face-to-face
+                firstPointA = NSMakePoint(bounds.width * 0.5, bounds.height * 0.5)
+                firstPointB = NSMakePoint(bounds.width * 0.12, bounds.height * 0.5)
+                firstPointC = NSMakePoint(bounds.width * 0.5, bounds.height * 0.12)
+
+                secondPointA = NSMakePoint(bounds.width * 0.5, bounds.height * 0.5)
+                secondPointB = NSMakePoint(bounds.width * 0.5, bounds.height * 0.88)
+                secondPointC = NSMakePoint(bounds.width * 0.88, bounds.height * 0.5)
+            } else {
+                // Fullscreen symbol that the angles of the two triangles are back-to-back
+                firstPointA = NSMakePoint(bounds.width * 0.25, bounds.height * 0.25)
+                firstPointB = NSMakePoint(bounds.width * 0.25, bounds.height * 0.65)
+                firstPointC = NSMakePoint(bounds.width * 0.65, bounds.height * 0.25)
+
+                secondPointA = NSMakePoint(bounds.width * 0.75, bounds.height * 0.75)
+                secondPointB = NSMakePoint(bounds.width * 0.35, bounds.height * 0.75)
+                secondPointC = NSMakePoint(bounds.width * 0.75, bounds.height * 0.35)
+            }
+            // Draw first triangle
+            symbol.move(to: firstPointA)
+            symbol.line(to: firstPointB)
+            symbol.line(to: firstPointC)
             symbol.close()
             lineColor.setFill()
             symbol.fill()
-            symbol.move(to: NSMakePoint(bounds.width * 0.75, bounds.height * 0.25))
-            symbol.line(to: NSMakePoint(bounds.width * 0.75, bounds.height * 2 / 3))
-            symbol.line(to: NSMakePoint(bounds.width * 1 / 3, bounds.height * 0.25))
+
+            // Clear path for the next triangle
+            symbol.removeAllPoints()
+
+            // Draw second triangle
+            symbol.move(to: secondPointA)
+            symbol.line(to: secondPointB)
+            symbol.line(to: secondPointC)
             symbol.close()
             lineColor.setFill()
             symbol.fill()
-            // maximize cross
-            // NSGraphicsContext.current?.shouldAntialias = false
-            // var symbol = NSBezierPath()
-            // symbol.move(to: NSMakePoint(bounds.width / 2, bounds.height * 0.20))
-            // symbol.line(to: NSMakePoint(bounds.width / 2, bounds.height * 0.80))
-            // symbol.move(to: NSMakePoint(bounds.width * 0.80, bounds.height / 2))
-            // symbol.line(to: NSMakePoint(bounds.width * 0.20, bounds.height / 2))
-            // symbol.lineWidth = 0.75
-            // NSGraphicsContext.current?.shouldAntialias = true
         } else if (type == .miniaturize) {
             NSGraphicsContext.current?.shouldAntialias = false
-            let symbol = NSBezierPath()
             symbol.move(to: NSMakePoint(bounds.width * 0.20, bounds.height / 2))
             symbol.line(to: NSMakePoint(bounds.width * 0.80, bounds.height / 2))
             symbol.lineWidth = 0.75
@@ -151,7 +167,6 @@ class TrafficLightButton: NSButton {
             symbol.stroke()
             NSGraphicsContext.current?.shouldAntialias = true
         } else if (type == .close) {
-            let symbol = NSBezierPath()
             symbol.move(to: NSMakePoint(bounds.width * 0.30, bounds.height * 0.30))
             symbol.line(to: NSMakePoint(bounds.width * 0.70, bounds.height * 0.70))
             symbol.move(to: NSMakePoint(bounds.width * 0.70, bounds.height * 0.30))
@@ -161,7 +176,6 @@ class TrafficLightButton: NSButton {
             symbol.stroke()
         } else if (type == .quit) {
             let mouthAngle = CGFloat(80) / 2
-            let symbol = NSBezierPath()
             symbol.appendArc(
                 withCenter: NSMakePoint(bounds.width / 2, bounds.height / 2),
                 radius: bounds.width * 0.27,
diff --git a/src/ui/main-window/ThumbnailView.swift b/src/ui/main-window/ThumbnailView.swift
index 2769aee2..8c32cdde 100644
--- a/src/ui/main-window/ThumbnailView.swift
+++ b/src/ui/main-window/ThumbnailView.swift
@@ -17,7 +17,7 @@ class ThumbnailView: NSStackView {
     var quitIcon = TrafficLightButton(.quit, NSLocalizedString("Quit app", comment: ""), windowsControlSize)
     var closeIcon = TrafficLightButton(.close, NSLocalizedString("Close window", comment: ""), windowsControlSize)
     var minimizeIcon = TrafficLightButton(.miniaturize, NSLocalizedString("Minimize/Deminimize window", comment: ""), windowsControlSize)
-    var maximizeIcon = TrafficLightButton(.fullscreen, NSLocalizedString("Fullscreen window", comment: ""), windowsControlSize)
+    var maximizeIcon = TrafficLightButton(.fullscreen, NSLocalizedString("Fullscreen/Defullscreen window", comment: ""), windowsControlSize)
     var hStackView: NSStackView!
     var mouseUpCallback: (() -> Void)!
     var mouseMovedCallback: (() -> Void)!
@@ -95,6 +95,9 @@ class ThumbnailView: NSStackView {
                         yOffset += ThumbnailView.windowsControlSize + ThumbnailView.windowsControlSpacing
                     }
                 }
+                // Force the icons to redraw, or after clicking the fullscreen button,
+                // it will still appear to be in fullscreen mode.
+                icon.display()
             }
         }
     }