Avoid selecting invalid tab when removing last page from wxOSX wxNotebook.

Closes #15897 (backport of r75663 from trunk).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@76319 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/cocoa/notebook.mm

@@ -194,7 +194,8 @@ public:
         // avoid 'changed' events when setting the tab programmatically
         wxTabViewController* controller = [slf delegate];
         [slf setDelegate:nil];
-        [slf selectTabViewItemAtIndex:(value-1)];
+        if ( value > 0 )
+            [slf selectTabViewItemAtIndex:(value-1)];
         [slf setDelegate:controller];
     }