GUI: swing issues
show cause in a stacktrace
GUI: fix swing issues with dialogs

fixes also:

java.lang.NullPointerException
null
javax.swing.plaf.basic.BasicProgressBarUI.updateSizes(BasicProgressBarUI.java:488)
javax.swing.plaf.basic.BasicProgressBarUI.getBox(BasicProgressBarUI.java:445)
javax.swing.plaf.basic.BasicProgressBarUI.setAnimationIndex(BasicProgressBarUI.java:942)
javax.swing.plaf.basic.BasicProgressBarUI.incrementAnimationIndex(BasicProgressBarUI.java:1000)
javax.swing.plaf.basic.BasicProgressBarUI$Animator.actionPerformed(BasicProgressBarUI.java:1208)
javax.swing.Timer.fireActionPerformed(Timer.java:313)