src/java.desktop/macosx/native/libawt_lwawt/awt/AWTWindow.m

@@ -212,11 +212,11 @@
 
     if (IS(styleBits, TEXTURED))      type |= NSTexturedBackgroundWindowMask;
     if (IS(styleBits, UNIFIED))       type |= NSUnifiedTitleAndToolbarWindowMask;
     if (IS(styleBits, UTILITY))       type |= NSUtilityWindowMask;
     if (IS(styleBits, HUD))           type |= NSHUDWindowMask;
-    if (IS(styleBits, SHEET))         type |= NSDocModalWindowMask;
+    if (IS(styleBits, SHEET))         type |= NSWindowStyleMaskDocModalWindow;
     if (IS(styleBits, NONACTIVATING)) type |= NSNonactivatingPanelMask;
 
     return type;
 }
 

@@ -271,11 +271,16 @@
                     frameRect:(NSRect)rect
                   contentView:(NSView *)view
 {
 AWT_ASSERT_APPKIT_THREAD;
 
-    NSUInteger styleMask = [AWTWindow styleMaskForStyleBits:bits];
+    NSUInteger newBits = bits;
+    if (IS(bits, SHEET) && owner == nil) {
+        newBits = bits & ~NSWindowStyleMaskDocModalWindow;
+    }
+    NSUInteger styleMask = [AWTWindow styleMaskForStyleBits:newBits];
+
     NSRect contentRect = rect; //[NSWindow contentRectForFrameRect:rect styleMask:styleMask];
     if (contentRect.size.width <= 0.0) {
         contentRect.size.width = 1.0;
     }
     if (contentRect.size.height <= 0.0) {

@@ -287,11 +292,12 @@
     if (self == nil) return nil; // no hope
 
     if (IS(bits, UTILITY) ||
         IS(bits, NONACTIVATING) ||
         IS(bits, HUD) ||
-        IS(bits, HIDES_ON_DEACTIVATE))
+        IS(bits, HIDES_ON_DEACTIVATE) ||
+        IS(bits, SHEET))
     {
         self.nsWindow = [[AWTWindow_Panel alloc] initWithDelegate:self
                             frameRect:contentRect
                             styleMask:styleMask
                           contentView:view];

@@ -317,10 +323,14 @@
 
     if (IS(self.styleBits, IS_POPUP)) {
         [self.nsWindow setCollectionBehavior:(1 << 8) /*NSWindowCollectionBehaviorFullScreenAuxiliary*/];
     }
 
+    if (IS(bits, SHEET) && owner != nil) {
+        [self.nsWindow setStyleMask: NSWindowStyleMaskDocModalWindow];
+    }
+
     return self;
 }
 
 + (BOOL) isAWTWindow:(NSWindow *)window {
     return [window isKindOfClass: [AWTWindow_Panel class]] || [window isKindOfClass: [AWTWindow_Normal class]];