From c0c244a45d2db9314e048066b99ce0df6947410b Mon Sep 17 00:00:00 2001
From: Bastian Schmidt <batzen@gmx.org>
Date: Sun, 11 Aug 2019 16:43:33 +0200
Subject: [PATCH] Improve check for RD "equality"

Only check RDs that have keys and only if first RD has at least as many keys as second
---
 src/MahApps.Metro/ThemeManager/ThemeManager.cs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/MahApps.Metro/ThemeManager/ThemeManager.cs b/src/MahApps.Metro/ThemeManager/ThemeManager.cs
index 8aaa5c6d16..913cae0845 100644
--- a/src/MahApps.Metro/ThemeManager/ThemeManager.cs
+++ b/src/MahApps.Metro/ThemeManager/ThemeManager.cs
@@ -913,8 +913,13 @@ private static bool AreResourceDictionarySourcesEqual(ResourceDictionary first,
                 return false;
             }
 
-            if (first.Source.IsNull()
+            // If RD does not have a source, but both have keys and the first one has at least as many keys as the second,
+            // then compares their values.
+            if ((first.Source.IsNull()
                 || second.Source.IsNull())
+                && first.Keys.Count > 0
+                && second.Keys.Count > 0
+                && first.Keys.Count >= second.Keys.Count)
             {
                 try
                 {