#3 NullPointerException when deleting Attributes

[Anonymous]

In certain contexts, when I want to delete an
attribute, I get this errormessage and nothing happens:

java.lang.NullPointerException
at
lattice.util.concept.DefaultFormalAttribute.equals(DefaultFormalAttribute.java:61)
at javax.swing.JList.setSelectedValue(JList.java:1827)
at
javax.swing.plaf.basic.BasicOptionPaneUI.getMessage(BasicOptionPaneUI.java:478)
at
javax.swing.plaf.basic.BasicOptionPaneUI.createMessageArea(BasicOptionPaneUI.java:331)
at
javax.swing.plaf.basic.BasicOptionPaneUI.installComponents(BasicOptionPaneUI.java:154)
at
javax.swing.plaf.basic.BasicOptionPaneUI$PropertyChangeHandler.propertyChange(BasicOptionPaneUI.java:1156)
at
javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(SwingPropertyChangeSupport.java:264)
at
javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(SwingPropertyChangeSupport.java:232)
at
javax.swing.JComponent.firePropertyChange(JComponent.java:3819)
at
javax.swing.JOptionPane.setInitialSelectionValue(JOptionPane.java:2030)
at
javax.swing.JOptionPane.showInputDialog(JOptionPane.java:550)
at
lattice.gui.RelationalContextEditor.removeFormalAttribute(RelationalContextEditor.java:1157)
at
lattice.gui.RelationalContextEditor.actionPerformed(RelationalContextEditor.java:667)
at
javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)
at
javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)
at
javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
at
javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
at
javax.swing.AbstractButton.doClick(AbstractButton.java:289)
at
javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1113)
at
javax.swing.plaf.basic.BasicMenuItemUI$MouseInputHandler.mouseReleased(BasicMenuItemUI.java:943)
at
java.awt.Component.processMouseEvent(Component.java:5100)
at java.awt.Component.processEvent(Component.java:4897)
at java.awt.Container.processEvent(Container.java:1569)
at
java.awt.Component.dispatchEventImpl(Component.java:3615)
at
java.awt.Container.dispatchEventImpl(Container.java:1627)
at java.awt.Component.dispatchEvent(Component.java:3477)
at
java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3483)
at
java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)
at
java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)
at
java.awt.Container.dispatchEventImpl(Container.java:1613)
at java.awt.Window.dispatchEventImpl(Window.java:1606)
at java.awt.Component.dispatchEvent(Component.java:3477)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
at
java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

I'm using a self-compiled 2.0-beta Version of Galicia.
One of the specific contexts is a Galicia-generated
scaling-context for MV-FCA.