Fix logic behind Mac theme variant inference

src/MacVim/MMVimController.m

@@ -163,6 +163,8 @@ - (void)handleBrowseForFile:(NSDictionary *)attr;
 - (void)handleShowDialog:(NSDictionary *)attr;
 - (void)handleDeleteSign:(NSDictionary *)attr;
 - (void)setToolTipDelay:(NSTimeInterval)seconds;
+- (void)themeChanged:(NSNotification *)notification;
+- (void)themeChangedOnMainThread;
 @end
 
 
@@ -201,6 +203,10 @@ - (id)initWithBackend:(id)backend pid:(int)processIdentifier
             selector:@selector(connectionDidDie:)
                 name:NSConnectionDidDieNotification object:connection];
 
+    [NSDistributedNotificationCenter.defaultCenter addObserver:self
+            selector:@selector(themeChanged:)
+                name:@"AppleInterfaceThemeChangedNotification" object:nil];
+
     // Set up a main menu with only a "MacVim" menu (copied from a template
     // which itself is set up in MainMenu.nib).  The main menu is populated
     // by Vim later on.
@@ -224,7 +230,7 @@ - (id)initWithBackend:(id)backend pid:(int)processIdentifier
 
     // After MMVimController's initialization is completed,
     // set up the variable `v:os_appearance`.
-    [self appearanceChanged:getCurrentAppearance([windowController vimView].effectiveAppearance)];
+    [self appearanceChanged:getCurrentAppearance(NSApp.effectiveAppearance)];
 
     return self;
 }
@@ -1910,6 +1916,14 @@ - (void)setToolTipDelay:(NSTimeInterval)seconds
     }
 }
 
+- (void)themeChanged:(NSNotification *)notification {
+    [self performSelectorOnMainThread:@selector(themeChangedOnMainThread) withObject:nil waitUntilDone:false];
+}
+
+- (void)themeChangedOnMainThread {
+    [self appearanceChanged:getCurrentAppearance(NSApp.effectiveAppearance)];
+}
+
 @end // MMVimController (Private)
 
 

src/MacVim/MMVimView.m

@@ -664,10 +664,6 @@ - (void)setFrame:(NSRect)frame
     [self frameSizeMayHaveChanged:NO];
 }
 
-- (void)viewDidChangeEffectiveAppearance
-{
-    [vimController appearanceChanged:getCurrentAppearance(self.effectiveAppearance)];
-}
 @end // MMVimView