FULL PRODUCT VERSION :
Java(TM) SE Runtime Environment (build 1.7.0-ea-b134)
Java HotSpot(TM) 64-Bit Server VM (build 21.0-b04, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Red Hat Enterprise Linux Server release 5.3 x86_64 GNU/Linux

EXTRA RELEVANT SYSTEM CONFIGURATION :
X11 client is running onto x86_64 RedHat Linux
X11 server is cygwinX11 in multiwindow mode on a MS Windows PC

A DESCRIPTION OF THE PROBLEM :
A Swing Application which is running as X11 client on a x86_64 RedHat Linux, uses a cygwinX11 server in order to display the gui on a PC with MS Windows XP.
Everytime when the window of the java application is minimized and maximized afterwards, the KeyboardInputFocus to every JTextField is
lost and will never establish again. Buttons, Sliders and so on are working, but not the KeyBoard Focus of JTextField or TextArea's.
The effect is the same with other X11 server's based on cygwin/X11 in multiwindow mode. The KeyboardFocus ist also lost when other Window Manager functions are triggered e.g. by opening/closing JDialogs.

REGRESSION. Last worked in version 6u24

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1 start cygwinX11 server on a MSWindows PC in multiwindow mode
2 allow the unix host access to cygwinX11 server
3 set DISPLAY environment variable of unix host to X11 server of the PC
4 start swing sample application on unix host with java 1.7
5 the sample application appears at the Windows PC
6 type something into the JTextField
7 minimize/maximize the application
8 now it is impossible to enter text in to JTextField (maybe already at 6)

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
After invoking the WindowManager e.g. by minimze/maximize of swing
application, the JTextField can never be used again for textinput by
keyboard. The text input cursor is not visible any more. Only Copy/Paste
is still working.
ACTUAL -
The results are always the same and can be reproduced anytime.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
There are no error messages displayed.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.*;

class KBFocusTest extends JFrame
{
    KBFocusTest()
    {
        super("KBFocusTest");
        JTextField text = new JTextField("try to edit!");
        add(text);
        pack();
        setVisible(true);
    }

    public static void main(String[] args)
    {
        KBFocusTest kbfocusTest = new KBFocusTest();
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
The application is working with java1.5 or java1.6. But java1.5 is outdated and java1.6 contains another X11 problem

the application is working with java1.7 when CygwinX11 is used in rootless mode with a separate WindowManager. But this is rather
uncomfortable to use.