A DESCRIPTION OF THE PROBLEM :
An hyperlink is not visible when inside a selected TreeItem, the hyperlink color is the same as the background color. It is a trivial css bug and has been solved in JDK-8094252 for TreeItems.
Should the color be white --> Like in JDK-8094252.

Fix the following way (modena.css -> search for: /* Fix for RT-37971 */):
.cell:selected .hyperlink,
.cell:selected .hyperlink:hover,
.cell:selected .hyperlink:hover:visited,
.tree-table-row-cell:selected .hyperlink,
.table-row-cell:selected .hyperlink,
.tree-table-row-cell:selected .hyperlink:hover,
.table-row-cell:selected .hyperlink:hover,
.tree-table-row-cell:selected .hyperlink:hover:visited,
.table-row-cell:selected .hyperlink:hover:visited {
    -fx-text-fill: -fx-text-background-color;
}



CUSTOMER SUBMITTED WORKAROUND :
add the following css code:
.cell:selected .hyperlink,
.cell:selected .hyperlink:hover,
.cell:selected .hyperlink:hover:visited,
.tree-table-row-cell:selected .hyperlink,
.table-row-cell:selected .hyperlink,
.tree-table-row-cell:selected .hyperlink:hover,
.table-row-cell:selected .hyperlink:hover,
.tree-table-row-cell:selected .hyperlink:hover:visited,
.table-row-cell:selected .hyperlink:hover:visited {
    -fx-text-fill: -fx-text-background-color;
}


FREQUENCY : always