JavaFx：TreeTableView箭头参考

Question

How can I get a reference to the expand/collapse "arrow" in a TreeTableView?

I cannot provide any code, since, I didn't really know what to look for.

Here is an image that shows what I need. The highlighted arrows are which I need.

I want to remove it, while keeping the collapse/expand mechanism(which works also if I click on the row itself), or making it transparent via css.

Answer 1

Set the background of the arrow to transparent via CSS stylesheet. The CSS below contains code for both TreeTableView and TreeView , since you write about TreeTableView but your screenshot shows a TreeView :

.tree-cell .arrow,
.tree-table-row-cell .arrow {
    -fx-background-color: transparent;
}