JFrame setlocation problems on linux

Question

When you drag a JFrame, you can move it anywhere you want, even if some of its boundary goes outside the screen...
Fortunately It's true on windows, mac and linux SUN JREs.
On windows and mac, you get the same effect if you decide to do it programatically with for example :
package testframe;
import javax.swing.JFrame;
public class Main {
    public static void main(String[] args) {
    JFrame jf=new JFrame();
    jf.setVisible(true);
    jf.setSize(400, 400);
    jf.setLocation(-300, 50);
}But this code doesn't work as expected on linux distros. I tried on kde, gnome and xfce, and I always get the same problem : the JRE (probably because of calls to window manager) refuses to place the window a little bit outside the screen boundaries. So in my example, jf.setLocation(-300,50) have the same effect as jf.setLocation(0,50).
Of course, when the windows appear at the (0,50) coordinates, it's always possible on linux to move it manually to a negative x-coordinate place.
setBounds method will lead to the same trouble...
Of course this piece of code is only here to show exactly what's wrong on linux sun jre's. In my "real code", I need to deal with undecorated Jframes, so I have to manage myself the mousepressed and mousedragged events on my custom titlebar, and I would really want the linux version of my application behave the same as windows and mac versions ...
The weird thing is that if I try to do that with JWindows in place of JFrames, it work's fine on Linux as well. But the problem is not here : in my case I need JFrames...
Anyone knows how to fix this on linux ?

Answer 1

When you drag a JFrame, you can move it anywhere you want, even if some of its boundary goes outside the screen...
Fortunately It's true on windows, mac and linux SUN JREs.
On windows and mac, you get the same effect if you decide to do it programatically with for example :
package testframe;
import javax.swing.JFrame;
public class Main {
    public static void main(String[] args) {
    JFrame jf=new JFrame();
    jf.setVisible(true);
    jf.setSize(400, 400);
    jf.setLocation(-300, 50);
}But this code doesn't work as expected on linux distros. I tried on kde, gnome and xfce, and I always get the same problem : the JRE (probably because of calls to window manager) refuses to place the window a little bit outside the screen boundaries. So in my example, jf.setLocation(-300,50) have the same effect as jf.setLocation(0,50).
Of course, when the windows appear at the (0,50) coordinates, it's always possible on linux to move it manually to a negative x-coordinate place.
setBounds method will lead to the same trouble...
Of course this piece of code is only here to show exactly what's wrong on linux sun jre's. In my "real code", I need to deal with undecorated Jframes, so I have to manage myself the mousepressed and mousedragged events on my custom titlebar, and I would really want the linux version of my application behave the same as windows and mac versions ...
The weird thing is that if I try to do that with JWindows in place of JFrames, it work's fine on Linux as well. But the problem is not here : in my case I need JFrames...
Anyone knows how to fix this on linux ?