diff --git a/src/nsterm.m b/src/nsterm.m
index 0b43c04c0b..e6f650467d 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -429,15 +429,13 @@ - (NSColor *)colorUsingDefaultColorSpace
 
    These flags will be OR'd or XOR'd with the NSWindow's styleMask
    property depending on what we're doing. */
-#ifdef NS_IMPL_COCOA
-#define FRAME_DECORATED_FLAGS NSWindowStyleMaskTitled
-#else
 #define FRAME_DECORATED_FLAGS (NSWindowStyleMaskTitled              \
                                | NSWindowStyleMaskResizable         \
                                | NSWindowStyleMaskMiniaturizable    \
                                | NSWindowStyleMaskClosable)
-#endif
-#define FRAME_UNDECORATED_FLAGS NSWindowStyleMaskBorderless
+#define FRAME_UNDECORATED_FLAGS (NSWindowStyleMaskResizable         \
+                               | NSWindowStyleMaskMiniaturizable    \
+                               | NSWindowStyleMaskClosable)
 
 /* TODO: get rid of need for these forward declarations */
 static void ns_condemn_scroll_bars (struct frame *f);
@@ -1883,8 +1881,7 @@ -(void)remove
       if (NILP (new_value))
         {
           FRAME_UNDECORATED (f) = false;
-          [window setStyleMask: ((window.styleMask | FRAME_DECORATED_FLAGS)
-                                  ^ FRAME_UNDECORATED_FLAGS)];
+          [window setStyleMask: FRAME_DECORATED_FLAGS];
 
           [view createToolbar: f];
         }
@@ -1894,8 +1891,7 @@ -(void)remove
           /* Do I need to release the toolbar here? */
 
           FRAME_UNDECORATED (f) = true;
-          [window setStyleMask: ((window.styleMask | FRAME_UNDECORATED_FLAGS)
-                                 ^ FRAME_DECORATED_FLAGS)];
+          [window setStyleMask: FRAME_UNDECORATED_FLAGS];
         }
 
       /* At this point it seems we don't have an active NSResponder,