Fix 'flicker' during window presentation caused by overly-broad early-out criteria.

src/MacVim/MMAppController.m

@@ -769,6 +769,7 @@ fsEventCallback(ConstFSEventStreamRef streamRef,
         if (!screen)
             screen = [win screen];
 
+        BOOL willSwitchScreens = screen != [win screen];
         if (cascadeFrom) {
             // Do manual cascading instead of using
             // -[MMWindow cascadeTopLeftFromPoint:] since it is rather
@@ -795,7 +796,14 @@ fsEventCallback(ConstFSEventStreamRef streamRef,
             ASLogNotice(@"Window not on screen, don't constrain position");
         }
 
-        [win setFrameTopLeftPoint:topLeft];
+        // setFrameTopLeftPoint will trigger a resize event if the window is
+        // moved across monitors; at this point such a resize would incorrectly
+        // constrain the window to the default vim dimensions, so a specialized
+        // method is used that will avoid that behavior.
+        if (willSwitchScreens)
+            [windowController moveWindowAcrossScreens:topLeft];
+        else
+            [win setFrameTopLeftPoint:topLeft];
     }
 
     if (1 == [vimControllers count]) {

src/MacVim/MMWindowController.h

@@ -45,6 +45,7 @@
     NSPoint             userTopLeft;
     NSPoint             defaultTopLeft;
     NSToolbar           *toolbar;
+    BOOL                resizingDueToMove;
 }
 
 - (id)initWithVimController:(MMVimController *)controller;
@@ -55,6 +56,7 @@
 - (void)cleanup;
 - (void)openWindow;
 - (BOOL)presentWindow:(id)unused;
+- (void)moveWindowAcrossScreens:(NSPoint)origin;
 - (void)updateTabsWithData:(NSData *)data;
 - (void)selectTabWithIndex:(int)idx;
 - (void)setTextDimensionsWithRows:(int)rows columns:(int)cols isLive:(BOOL)live

src/MacVim/MMWindowController.m

@@ -150,6 +150,8 @@
     self = [super initWithWindow:win];
     if (!self) return nil;
 
+    resizingDueToMove = NO;
+
     vimController = controller;
     decoratedWindow = [win retain];
 
@@ -347,6 +349,18 @@
     return YES;
 }
 
+- (void)moveWindowAcrossScreens:(NSPoint)topLeft
+{
+    // HACK! This method moves a window to a new origin and to a different
+    // screen. This is primarily useful to avoid a scenario where such a move
+    // will trigger a resize, even though the frame didn't actually change size.
+    // This method should not be called unless the new origin is definitely on
+    // a different screen, otherwise the next legitimate resize message will
+    // be skipped.
+    resizingDueToMove = YES;
+    [[self window] setFrameTopLeftPoint:topLeft];
+}
+
 - (void)updateTabsWithData:(NSData *)data
 {
     [vimView updateTabsWithData:data];
@@ -993,7 +1007,13 @@
 
 - (void)windowDidResize:(id)sender
 {
-    if (!setupDone || fullScreenEnabled || !windowPresented) return;
+    if (resizingDueToMove)
+    {
+        resizingDueToMove = NO;
+        return;
+    }
+
+    if (!setupDone || fullScreenEnabled) return;
 
     // NOTE: Since we have no control over when the window may resize (Cocoa
     // may resize automatically) we simply set the view to fill the entire