NullPointerException on Filters

[Ankita Taunk]

Hi,

I started using this filter recently but faced an issue when I click on the dropdown arrow for filtering.

This is the error that's shown:

java.lang.NullPointerException
        at net.coderazzi.filters.gui.editor.PopupComponent.setPopupFocused(PopupComponent.java:290)
        at net.coderazzi.filters.gui.editor.FilterEditor.triggerPopup(FilterEditor.java:458)
        at net.coderazzi.filters.gui.editor.FilterEditor$2.actionPerformed(FilterEditor.java:132)
        at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)
        at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)
        at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
        at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
        at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
        at java.desktop/java.awt.Component.processMouseEvent(Component.java:6635)
        at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
        at java.desktop/java.awt.Component.processEvent(Component.java:6400)
        at java.desktop/java.awt.Container.processEvent(Container.java:2263)
        at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5011)
        at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
        at java.desktop/java.awt.Component.dispatchEvent(Component.java:4843)
        at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)
        at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)
        at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488)
        at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)
        at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2772)
        at java.desktop/java.awt.Component.dispatchEvent(Component.java:4843)
        at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
        at java.base/java.security.AccessController.doPrivileged(Native Method)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
        at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
        at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
        at java.base/java.security.AccessController.doPrivileged(Native Method)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
        at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
        at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:969)
        at com.intellij.ide.IdeEventQueue.dispatchMouseEvent(IdeEventQueue.java:906)
        at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:836)
        at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$8(IdeEventQueue.java:449)
        at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:808)
        at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$9(IdeEventQueue.java:448)




Also, I tried to debug and I found the problem but I'm not sure how to solve it. 
When showChoices() is called in the FilterEditor, the popup and editor values are Invalid, and, so when it calls setPopUpFocused(true), their focusList is empty and it throws this exception. 

My table is simple too, all columns are string type and I have enabled AutoChoices.
TableFilterHeader filterHeader = new TableFilterHeader(table, AutoChoices.ENABLED); 

Please help me through this, I'm new, and I might be doing something wrong.