Update balloon eval on scroll wheel event

src/MacVim/MMBackend.m

@@ -1865,6 +1865,19 @@ static void netbeansReadCallback(CFSocketRef s,
 #endif
 
         gui_send_mouse_event(button, col, row, NO, flags);
+
+#ifdef FEAT_BEVAL
+        if (p_beval && balloonEval) {
+            // Update the balloon eval message after a slight delay (to avoid
+            // calling it too often).
+            [NSObject cancelPreviousPerformRequestsWithTarget:self
+                                             selector:@selector(bevalCallback:)
+                                               object:nil];
+            [self performSelector:@selector(bevalCallback:)
+                       withObject:nil
+                       afterDelay:MMBalloonEvalInternalDelay];
+        }
+#endif
     } else if (MouseDownMsgID == msgid) {
         if (!data) return;
         const void *bytes = [data bytes];

src/feature.h

@@ -1239,8 +1239,8 @@
  *			Only for GUIs where it was implemented.
  */
 #if (defined(FEAT_GUI_MOTIF) || defined(FEAT_GUI_ATHENA) \
-	|| defined(FEAT_GUI_GTK) || defined(FEAT_GUI_W32) \
-	|| defined(FEAT_GUI_MACVIM)) \
+	|| defined(FEAT_GUI_MACVIM) \
+	|| defined(FEAT_GUI_GTK) || defined(FEAT_GUI_W32)) \
 	&& (   ((defined(FEAT_TOOLBAR) || defined(FEAT_GUI_TABLINE)) \
 		&& !defined(FEAT_GUI_GTK) && !defined(FEAT_GUI_W32)) \
 	    || defined(FEAT_SUN_WORKSHOP) \