Crashing upon multipage pack copy

[Rubonnek]

After packing a multipage atlas, attempting to copy the pack with Ctrl-Shift-C will crash the UI.

Tested by packing all the images in PNGs.zip

Please paste the crash log in here (already in your clipboard) and, if possible, provide any information that may help to reproduce the issue.

java.lang.RuntimeException: Actor: VisTextButton: Ok
        at com.badlogic.gdx.scenes.scene2d.Actor.notify(Actor.java:192)
        at com.badlogic.gdx.scenes.scene2d.Actor.fire(Actor.java:152)
        at com.badlogic.gdx.scenes.scene2d.ui.Button.setChecked(Button.java:125)
        at com.badlogic.gdx.scenes.scene2d.ui.Button$1.clicked(Button.java:93)
        at com.badlogic.gdx.scenes.scene2d.utils.ClickListener.touchUp(ClickListener.java:88)
        at com.badlogic.gdx.scenes.scene2d.InputListener.handle(InputListener.java:71)
        at com.badlogic.gdx.scenes.scene2d.Stage.touchUp(Stage.java:355)
        at com.crashinvaders.common.PrioritizedInputMultiplexer$Wrapper.touchUp(PrioritizedInputMultiplexer.java:136)
        at com.crashinvaders.common.PrioritizedInputMultiplexer.touchUp(PrioritizedInputMultiplexer.java:83)
        at com.badlogic.gdx.InputEventQueue.drain(InputEventQueue.java:70)
        at com.badlogic.gdx.backends.lwjgl3.DefaultLwjgl3Input.update(DefaultLwjgl3Input.java:189)
        at com.badlogic.gdx.backends.lwjgl3.Lwjgl3Window.update(Lwjgl3Window.java:394)
        at com.badlogic.gdx.backends.lwjgl3.Lwjgl3Application.loop(Lwjgl3Application.java:143)
        at com.badlogic.gdx.backends.lwjgl3.Lwjgl3Application.<init>(Lwjgl3Application.java:116)
        at com.crashinvaders.texturepackergui.desktop.ApplicationStarter.start(ApplicationStarter.java:57)
        at com.crashinvaders.texturepackergui.desktop.ApplicationStarter.main(ApplicationStarter.java:35)
Caused by: java.lang.NullPointerException
        at com.crashinvaders.texturepackergui.controllers.CommonDialogs$5.run(CommonDialogs.java:134)
        at com.crashinvaders.texturepackergui.controllers.CommonDialogs$8.changed(CommonDialogs.java:173)
        at com.badlogic.gdx.scenes.scene2d.utils.ChangeListener.handle(ChangeListener.java:28)
        at com.badlogic.gdx.scenes.scene2d.Actor.notify(Actor.java:188)
        ... 15 more
X Error of failed request:  BadAccess (attempt to access private resource denied)
  Major opcode of failed request:  2 (X_ChangeWindowAttributes)
  Serial number of failed request:  79
  Current serial number in output stream:  80

[metaphore]

Nicely spotted, thanks! Was a quick fix.

[Rubonnek]

Thank you!