How to style a custom TreeCell with CSS in ScalaFX? -

i want change background colour of custom treecell using css, setting style property on tree cell doesn't work. can style tree alternate yellow , grey cells css file looks this:

.tree-cell:disabled {     -fx-padding: 3 3 3 3;     -fx-background-color: white; }  .tree-cell:selected {     -fx-background-color: blue; }  .tree-cell:even {     -fx-background-color: yellow; }  .tree-cell:odd {     -fx-background-color: grey; }  .tree-cell:drag-over {     -fx-background-color: plum; } 

and change fill style of text event handler looks this:

  ondragentered = (event: dragevent) => {     val db = event.getdragboard     if (db.hascontent(customformat)) {       textfill = color.deepskyblue        style() = "tree-cell:drag-over"     }      event.consume()   } 

but style of tree cells doesn't change.

i found answer own question. css file looks this:

.tree-cell:disabled {     -fx-padding: 3 3 3 3;     -fx-background-color: white; }  .tree-cell:selected {     -fx-background-color: blue; }  .tree-cell:filled:even {     -fx-background-color: lightyellow; }  .tree-cell:filled:odd {     -fx-background-color: lightsteelblue; }  .tree-cell.drag-over:filled {     -fx-background-color: plum; } 

i plum colour when dragging on filled cell. empty cells stay white. in order here needed understand rules of "css specificity", although possible simplify finished css file make each case match 1 selector.

the scalafx code looks this:

import scala.collection.javaconversions._  // copy list, isn't modified in place. var oldstyleclass: util.collection[string] = styleclass.tolist  ondragentered = (event: dragevent) => {   val db = event.getdragboard   if (db.hascontent(customformat)) {     textfill = color.deepskyblue      // remember original style taking copy.     oldstyleclass = styleclass.tolist      // restyle filled cells .tree-cell.dragover:filled     // duration of drag     styleclass.add("drag-over")   }    event.consume() }  ondragexited = (event: dragevent) => {   val db = event.getdragboard   if (db.hascontent(customformat)) {     textfill = color.black   }    // restore original style.   styleclass.setall(oldstyleclass)    event.consume() } 

somewhere along way lost animation failed drop. otherwise i'm happy (but lonely in scalafx-land.)