fix exception during start up, when upgrade is available

java.lang.NullPointerException
null
javax.swing.BoxLayout.checkRequests(Unknown Source)
javax.swing.BoxLayout.preferredLayoutSize(Unknown Source)
javax.swing.plaf.basic.DefaultMenuLayout.preferredLayoutSize(Unknown
Source)
java.awt.Container.preferredSize(Unknown Source)
java.awt.Container.getPreferredSize(Unknown Source)
javax.swing.JComponent.getPreferredSize(Unknown Source)
javax.swing.JRootPane$RootLayout.layoutContainer(Unknown Source)
java.awt.Container.layout(Unknown Source)
java.awt.Container.doLayout(Unknown Source)