I have two JFrames:
- ApplicationsJFrame, which is my Main, and
- InsertApplicationsForm.
I'm setting the InsertApplicationsForm visible by clicking a Button in my ApplicationsJFrame. 
Every time I'm closing the InsertApplicationsForm the ApplicationsJFrame also closes, but the Program is still running, same when I minimize InsertApplicationsForm, ApplicationsJFrame minimizes, but wont maximize anymore...
ApplicationsJFrame:
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("T-AMS");
setFocusableWindowState(false);
InsertApplicationsForm:
public class InsertApplicationForm extends javax.swing.JFrame {
    /**
     * Creates new form InsertApplicationForm
     */
    public InsertApplicationForm() {
        initComponents();
    }
[...]
setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
        setTitle("Insert Application")
addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosed(java.awt.event.WindowEvent evt) {
                formWindowClosed(evt);
            }
        });
private void formWindowClosed(java.awt.event.WindowEvent evt) {                                  
        ApplicationsJFrame.insert = false;
    }
Open InsertApplicationsForm:
new InsertApplicationForm().setVisible(true);
 
     
    