CLONE - [SplitPane] Cannot set divider position in multiple splitpanes at once on button setOnAction()

In my application there are multiple splitpanes (one inheriting the other). When resizing the scene the divider position defaults (as set in the FXML) are not taken into account and the application therefore incorrectly displays the divider positions. I tried to solve this by adjusting the divider positions at a button click event (..setOnAction(new EventHandler<ActionEvent>()...) but when I click it only one splitpane at a time is adjusted. As I have 3 splitpanes I have to click the button 3 times to get all the adjustments. I am not sure whether this is because the click event is consumed after the first adjustment and subsequent repaint of the scene? Please advice what to do or provide a solution for the bug. Thanks!