[news.eclipse.platform.swt] [SWT] curious focus behaviour

[andre.saibel@xxxxxx (Andre)]

hello..

I recently stumbled over some curious focus behaviour:
if I call a widget's forceFocus() or setFocus() method, it works fine on
SWT.WIN32 (XP) but doesn't on SWT.motif (Linux and Solaris) and SWT.photon
(QNX). On SWT.gtk (Linux) it even may cause a stack overflow.

My questions are: is that a bug or is that _really_ a platform specific
behaviour? Is there I way to realy force a widget to get the focus - on
every platform? I thought that if it's part of the API it should work
everywhere..

Thanks in advance
Andre

PS: a short sample code that demonstrates this problem:

public class CuriousFocus
{
	public static void main(String[] args)
	{
		Display display = new Display();
		Shell shell = new Shell(display);
		
		final Canvas widget1 = new Canvas(shell, SWT.BORDER);
		widget1.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WHITE));		
		widget1.addFocusListener( new FocusListener()
		{
			public void focusGained(FocusEvent e)
			{
				System.out.println("widget1::focusGained()");
				widget1.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_RED));
				widget1.redraw();
			}

			public void focusLost(FocusEvent e)
			{
				System.out.println("widget1::focusLost()");
				widget1.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WHITE));
				widget1.redraw();
			}
		});

		final Canvas widget2 = new Canvas(shell, SWT.BORDER);
		widget2.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WHITE));
		widget2.addFocusListener( new FocusListener()
		{
			public void focusGained(FocusEvent e)
			{
				System.out.println("widget2::focusGained() \n");
				widget2.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_RED));
				widget2.redraw();
			}

			public void focusLost(FocusEvent e)
			{
				System.out.println("widget2::focusLost()");
				widget2.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WHITE));
				widget2.redraw();

				// grab keyboard focus forever here
				widget2.forceFocus();
				//widget2.setFocus();
			}
		});


		shell.setLayout( new FillLayout());
		shell.open();

		//shell.setSize(200, 100);
		shell.pack();

		while (!shell.isDisposed())
		{
			if (!display.readAndDispatch())
			{
				display.sleep();
			}
		}
		display.dispose();
	}
}