Fixed: setupViewFlags was not called when creating a view from a xib

Previously, the method setupViewFlags was not called when creating from a xib. This issue was introduced by the commit #448c2a2

Fixed #2380

AppKit/CPView.j

@@ -3720,6 +3720,7 @@ var CPViewAutoresizingMaskKey       = @"CPViewAutoresizingMask",
             _opacity = 1.0;
 
         [self setBackgroundColor:[aCoder decodeObjectForKey:CPViewBackgroundColorKey]];
+        [self _setupViewFlags];
 
         _theme = [CPTheme defaultTheme];
         _themeClass = [aCoder decodeObjectForKey:CPViewThemeClassKey];