force Jframe to be activated to gain focus on child

Question

I have a problem which I am stuck with about 3 days, I have read a lot of answers regarding my problem but none solved my issue.

Discription

1. I have java application which have two frames ,the main frame has a buttons. Once one is selected a new small frame is opened on the top of the main frame.

2. on the small frame I have text fields which changes depending on the button pressed on the main frame.

3. only on start I initialize the small frame but after the first time I use it just by changing the text field values

4. the small frame has an exit button once pressed the frame is hidden using Jframe.toback() and once a button is clicked I use Jframe.tofront() to make it visible.

The problem

when I press a button on the main frame I want the focus to be granted for the first text field,I need to see the mouse cursor on it.
When I start the first time the focus is granted to that text field and when I press the exit button and select another button it works but sometimes when I press very quickly the focus is not granted and the frame is not activated.
I need a way to force the small frame to be activated once opened.

when one of the buttons is clicked on the main frame I change the data in the small frame and run this code:

SwingUtilities.invokeLater(new Runnable() {

        public void run() {
            logger.debug("isDisplayable() + isFocusable() + isVisible());
                idField.grabFocus();

        }
    });

the first time I start the application everything works just fine because I use the method requestFocusInWindow() before the frame becomes visible.
After that the above code does not always works, it seems to me like a race condition.
How can I force the small frame gain focus once a button is clicked to be active?

thanks for any help.