FVWM: Java applications don't get keyboard focus

[Oleksandr Gavenko]

Commonly recommended:

Style "sun-awt-X11-*" Lenience

make Fvwm border decoration colors as if window is active (defined Alt+F4
close proper window) but application ignore/doesn't receive keyboard input.

Direct click inside window (not on decoration!) bring keyboard focus to
application.

Most common annoyances are:

* loosing keyboard focus in main application after closing popup dialog box
(like closing search box in editor)
* not getting keyboard focus after 'WindowList' (Alt+TAB)

I tested this program:

public static void main(String[] args) {
final JFrame frame = new JFrame("FrameDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JEditorPane editorPane = new JEditorPane();
JScrollPane editorScrollPane = new JScrollPane(editorPane);
editorScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
editorScrollPane.setPreferredSize(new Dimension(250, 145));
editorScrollPane.setMinimumSize(new Dimension(10, 10));

frame.add(editorScrollPane);

frame.setPreferredSize(new Dimension(200, 150));

frame.pack();
frame.setVisible(true);
}

with:

$ fluxbox
$ openbox

and switching between windows on Alt+TAB always return keyboard focus to
JEditorPane, while in Fvwm even with 'FPLenient' keyboard focus isn't received
until I clicked inside 'JEditorPane' area.

My settings are available at:

http://hg.defun.work/skel/file/df82d859f907/.xinitrc
http://hg.defun.work/skel/file/df82d859f907/.fvwm/config

It is painful to work with Java IDE with such Fvwm behavior. I live with this
issue since 2008 and already asked for help:

https://www.mail-archive.com/***@fvwm.org/msg02569.html

I can reproduce similar bug report in Java 8 and my Fvwm 1:2.6.7-2 (Debian):

https://bugs.openjdk.java.net/browse/JDK-6541872

I am not sure what other WMs/DEs do in order to keep Java application working
but 'Lenience' should try to do the same.