Open and save dialog fail to show

Open and save dialog fail to show if last opened file does not exist anymore and AMAPVox throws error:

Caused by: java.lang.IllegalArgumentException: Folder parameter must be a valid folder
	at javafx.graphics/com.sun.glass.ui.CommonDialogs.convertFolder(Unknown Source)
	at javafx.graphics/com.sun.glass.ui.CommonDialogs.showFileChooser(Unknown Source)
	at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.showFileChooser(Unknown Source)
	at javafx.graphics/javafx.stage.FileChooser.showDialog(Unknown Source)
	at javafx.graphics/javafx.stage.FileChooser.showOpenMultipleDialog(Unknown Source)
	at org.amapvox.gui.MainFrameController.addTask(MainFrameController.java:1166)
	at org.amapvox.gui.MainFrameController.onActionMenuAddTask(MainFrameController.java:662)