From 21b3bdc0550cb56caac7e0f41c2761cc20d94be6 Mon Sep 17 00:00:00 2001
From: xiaoy312 <xiaoyao312@gmail.com>
Date: Tue, 9 Jun 2020 11:56:08 -0400
Subject: [PATCH] fix(NavigationView): toggle pane button width when
 light-dismissed

---
 .../UI/Xaml/Controls/NavigationView/NavigationView.cs      | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/Uno.UI/UI/Xaml/Controls/NavigationView/NavigationView.cs b/src/Uno.UI/UI/Xaml/Controls/NavigationView/NavigationView.cs
index daa5e5c1b251..3c7bfb2c9142 100644
--- a/src/Uno.UI/UI/Xaml/Controls/NavigationView/NavigationView.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/NavigationView/NavigationView.cs
@@ -3034,12 +3034,15 @@ void UpdatePaneToggleSize()
 
 					if (!m_isClosedCompact && PaneTitle?.Length > 0)
 					{
-						if (splitView.DisplayMode == SplitViewDisplayMode.Overlay && IsPaneOpen)
+						// if splitView.IsPaneOpen changed directly by SplitView,
+						// the two-way binding haven't sync'd up IsPaneOpen yet.
+						var isPaneOpen = m_isOpenPaneForInteraction ? IsPaneOpen : splitView.IsPaneOpen;
+						if (splitView.DisplayMode == SplitViewDisplayMode.Overlay && isPaneOpen)
 						{
 							width = OpenPaneLength;
 							togglePaneButtonWidth = OpenPaneLength - (ShouldShowBackButton() ? c_backButtonWidth : 0);
 						}
-						else if (!(splitView.DisplayMode == SplitViewDisplayMode.Overlay && !IsPaneOpen))
+						else if (!(splitView.DisplayMode == SplitViewDisplayMode.Overlay && !isPaneOpen))
 						{
 							width = OpenPaneLength;
 							togglePaneButtonWidth = OpenPaneLength;