From c7d565fd0ca12af45ffa99a44b8e9977a1be74e9 Mon Sep 17 00:00:00 2001
From: MonkAlex <3amepob@gmail.com>
Date: Sun, 5 Aug 2018 11:11:39 +0400
Subject: [PATCH] #1798 Fix binding checkbox with three state.

---
 src/Avalonia.Controls/Primitives/ToggleButton.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Avalonia.Controls/Primitives/ToggleButton.cs b/src/Avalonia.Controls/Primitives/ToggleButton.cs
index dc9b70ab8c..1d2e2f2100 100644
--- a/src/Avalonia.Controls/Primitives/ToggleButton.cs
+++ b/src/Avalonia.Controls/Primitives/ToggleButton.cs
@@ -14,7 +14,7 @@ namespace Avalonia.Controls.Primitives
                 nameof(IsChecked),
                 o => o.IsChecked,
                 (o, v) => o.IsChecked = v,
-                unsetValue: false,
+                unsetValue: null,
                 defaultBindingMode: BindingMode.TwoWay);
 
         public static readonly StyledProperty<bool> IsThreeStateProperty =