iOS: small alphas disregarded

[mkempka]

This is my code:

        Shell parentShell = ui.getDisplay().getActiveShell();
        final Shell abortion = new Shell(parentShell, SWT.APPLICATION_MODAL);
        abortion.setAlpha(2);
        abortion.setLayout(new GridLayout());
        abortion.setMaximized(true);
        Composite touchReceiver = new Composite(abortion, SWT.NONE);
        touchReceiver.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
        touchReceiver.addMouseListener(new MouseAdapter() {
           @Override
            public void mouseUp(MouseEvent e) {
                abortion.dispose();
               // more code
            }
        });

These are the problems: In line 3, small alpha values have the following behaviour:

• If the alpha value is 0, 1, or 2, I don't receive the mouse event.
• Small values of alpha don't have an effent, the shell has always an alpha of about 100