private Button AddAnnotationButton(Annotation annotation)
{
var b = new Button();
b.Size = new Size(ButtonHeight, ButtonHeight);
b.Image = annotation.GetOpenOrClosedImage(ButtonImageHeight);
b.Tag = annotation;
b.FlatStyle = FlatStyle.Flat;
b.FlatAppearance.BorderSize = 0;
toolTip1.SetToolTip(b, annotation.GetTextForToolTip());
b.Click += new EventHandler(OnExistingAnnotationButtonClick);
_buttonsPanel.Controls.Add(b);
return b;
}
