Launch the attached FXML example (e.g. Preview with Scene Builder).
This is a SplitPane that contains a GridPane. The first column has a width with a decimal value.
Move the SplitPane divider on the left : the application hang :

Stack trace:
javafx.scene.layout.GridPane.growOrShrinkColumnWidths(GridPane.java:1694)
javafx.scene.layout.GridPane.adjustColumnWidths(GridPane.java:1668)
javafx.scene.layout.GridPane.layoutChildren(GridPane.java:1481)
javafx.scene.Parent.layout(Parent.java:1018)
javafx.scene.Parent.layout(Parent.java:1028)
javafx.scene.Parent.layout(Parent.java:1028)
javafx.scene.Parent.layout(Parent.java:1028)
javafx.scene.Scene.layoutDirtyRoots(Scene.java:513)
javafx.scene.Scene.doLayoutPass(Scene.java:484)
javafx.scene.Scene.access$3900(Scene.java:169)
javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2199)
com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:363)
com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:460)
com.sun.javafx.tk.quantum.QuantumToolkit$9.run(QuantumToolkit.java:329)
com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
com.sun.glass.ui.win.WinApplication$2$1.run(WinApplication.java:67)
java.lang.Thread.run(Thread.java:722)