internal ActivityDesignerGlyphCollection GetDesignerGlyphs(ActivityDesigner designer)
 {
     ActivityDesignerGlyphCollection glyphs = new ActivityDesignerGlyphCollection();
     if (designer.Glyphs != null)
     {
         glyphs.AddRange(designer.Glyphs);
     }
     foreach (IDesignerGlyphProvider provider in this.designerGlyphProviders)
     {
         ActivityDesignerGlyphCollection collection = provider.GetGlyphs(designer);
         if (collection != null)
         {
             glyphs.AddRange(collection);
         }
     }
     glyphs.Sort(new Comparison<DesignerGlyph>(DesignerGlyph.OnComparePriority));
     return glyphs;
 }