Run main3.java from attached application.
Set sliders' value (which bidirectionally manage GraphicTextGap value) to 130 or greater.
You will get such exception:

java.lang.StringIndexOutOfBoundsException: String index out of range: -1
        at java.lang.String.substring(String.java:1937)
        at com.sun.javafx.scene.control.skin.Utils.computeClippedWrappedText(Utils.java:404)
        at com.sun.javafx.scene.control.skin.LabeledSkinBase.updateDisplayedText(LabeledSkinBase.java:424)
        at com.sun.javafx.scene.control.skin.LabeledSkinBase.layoutLabelInArea(LabeledSkinBase.java:867)
        at com.sun.javafx.scene.control.skin.CheckBoxSkin.layoutChildren(CheckBoxSkin.java:84)
        at javafx.scene.Parent.layout(Parent.java:900)
        at javafx.scene.Parent.layout(Parent.java:910)
        at javafx.scene.Parent.layout(Parent.java:910)
        at javafx.scene.Scene.layoutDirtyRoots(Scene.java:455)
        at javafx.scene.Scene.doLayoutPass(Scene.java:428)
        at javafx.scene.Scene.access$3000(Scene.java:133)
        at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:1797)
        at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:292)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:385)
        at com.sun.javafx.tk.quantum.QuantumToolkit$8.run(QuantumToolkit.java:311)
        at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
        at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
        at com.sun.glass.ui.win.WinApplication$2$1.run(WinApplication.java:62)
        at java.lang.Thread.run(Thread.java:662)