utton", "PanelExpanderButton", "ContextMenuButton", and "CheckBoxButton".
"ContextMenuButton"s are typically used inside of "ContextMenu" Panels;
"CheckBoxButton"s are used in the implementation of "CheckBox" Panels.
</p>
<p>
These predefined panels can be used as if they were <a href="../api/symbols/Panel.html" target="api">Panel</a>-derived classes in calls to <a href="../api/symbols/GraphObject.html#make" target="api">GraphObject.make</a>.
They are implemented as simple visual trees of <a href="../api/sy