I have a textbox & the slider. When the stage is visible , i click on the slider to rotate the texbox. When i press tab key from transfer the focus from slider to textbox. i see following debug value on the console .
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getComponentAfter null
getFirstComponent null

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------ TestCase -----
import javafx.scene.control.*;
import javafx.scene.*;
import javafx.stage.*;
import javafx.ext.swing.SwingSlider;


var rotateSlider :SwingSlider = SwingSlider {
minimum: 0
maximum: 360
value: 0
vertical: false
}

var t1 : TextBox = TextBox {

     translateX : 40
     translateY : 40
     text: "Hello World"
     columns: 12
     selectOnFocus: true
     rotate : bind rotateSlider.value
 }


Stage {
     scene: Scene {
         content: [rotateSlider ,t1 ]
     }
}
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i observed the same both on vista & ubundu.