 applications want to copy only a part of the label, e.g. an ID shown by
 the label like this: "Customer account #12345678". The copy content supplier can then
 decide to just return the ID "12345678" instead of the whole string. The default
 supplier however returns the whole string.</dd>
<dt>Returns:</dt>
<dd>the value of the <code>copyContentSupplier</code> property</dd>
<dt>See Also:</dt>
<dd>
<ul class="see-list-long">
<li><a href="#setCopyContentSupplier(java.util.function.Supplier)"><code>setCopyCont