ClassCastException is thrown sometimes when 'enter' is pressed in empty attachment field

[vogoltsov]

[2019/02/13 17:14:29] [message] java.lang.ClassCastException: java.base/java.lang.String cannot be cast to com.github.vogoltsov.vp.plugins.confluence.client.model.Attachment
[2019/02/13 17:14:29] [message] at java.base/java.util.Optional.map(Unknown Source)
[2019/02/13 17:14:29] [message] at com.github.vogoltsov.vp.plugins.common.swing.AutoCompleteComboBox$AutoCompleteComboBoxEditor.setItem(AutoCompleteComboBox.java:288)
[2019/02/13 17:14:29] [message] at com.github.vogoltsov.vp.plugins.common.swing.AutoCompleteComboBox$AutoCompleteComboBoxEditor.updateItem(AutoCompleteComboBox.java:281)
[2019/02/13 17:14:29] [message] at com.github.vogoltsov.vp.plugins.common.swing.AutoCompleteComboBox$AutoCompleteComboBoxEditor.focusGained(AutoCompleteComboBox.java:321)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.AWTEventMulticaster.focusGained(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.AWTEventMulticaster.focusGained(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.AWTEventMulticaster.focusGained(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.AWTEventMulticaster.focusGained(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Component.processFocusEvent(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Component.processEvent(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Container.processEvent(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Component.dispatchEventImpl(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Component.dispatchEventImpl(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventQueue.access$500(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventQueue$3.run(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventQueue$3.run(Unknown Source)
[2019/02/13 17:14:29] [message] at java.base/java.security.AccessController.doPrivileged(Native Method)
[2019/02/13 17:14:29] [message] at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
[2019/02/13 17:14:29] [message] at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
[2019/02/13 17:14:29] [message] at java.base/java.security.AccessController.doPrivileged(Native Method)
[2019/02/13 17:14:29] [message] at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.WaitDispatchSupport$2.run(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.WaitDispatchSupport$4.run(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.WaitDispatchSupport$4.run(Unknown Source)
[2019/02/13 17:14:29] [message] at java.base/java.security.AccessController.doPrivileged(Native Method)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.WaitDispatchSupport.enter(Unknown Source)
[2019/02/13 17:14:29] [message] at java.desktop/java.awt.Dialog.show(Unknown Source)
[2019/02/13 17:14:29] [message] at v.bzc.f.show(:438)
[2019/02/13 17:14:29] [message] at v.bzc.i.bJ_(:760)
[2019/02/13 17:14:29] [message] at v.bea.z.showDialog(:93)
[2019/02/13 17:14:29] [message] at com.github.vogoltsov.vp.plugins.confluence.action.ExportDiagramAsActionController.performAction(ExportDiagramAsActionController.java:23)