Java Layout not showing components (sometimes)

Question

I\'m writing a MathQuiz for my pupils including JLatexMath for rendering and jinput for the buzzers. The problem is, that sometimes (like every fourth time) when I start the pro

Answer 1

Start by moving setVisible(true); to the end of the constructor.

Instead of been here...

public Shell() {
    super("blaBla");
    this.setSize(800, 600);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
    //...
} 

Move it here...

public Shell() {
    super("blaBla");
    //...
    add(Box.createVerticalStrut(20));
    add(formulaPanel);
    setVisible(true);
} 

To protect against any other possible graphical glitches, you should always start you UI's from within the Event Dispatching Thread, see Initial Threads for more details