Provide more options to configure the NotificationPopup #4487

Point size = popup.getShell().getSize();
Point location = popup.getShell().getLocation();
popup.getShell().pack();
popup.getShell().setLocation(location.x, location.y + (size.y - popup.getShell().getSize().y));

NotificationPopup.forDisplay(Display.getDefault())
    .text("A problem occurred.")
    .title("Warning", true)
    .minHeight(0)
    .maxWidth(500)
    .paddingEdge(10)
    .open();

    static void attachPopupFollower(Shell parentShell, Shell popupShell, int padding) {
        Listener moveListener = e -> {
            if (parentShell == null || parentShell.isDisposed()) {
                return;
            }
            if (popupShell == null || popupShell.isDisposed()) {
                return;
            }

            Rectangle clientArea = parentShell.getClientArea();
            Point clientOriginOnDisplay = parentShell.toDisplay(clientArea.x, clientArea.y);
            Point popupSize = popupShell.getSize();

            int x = clientOriginOnDisplay.x + clientArea.width - popupSize.x - padding; //use the configured paddingEdge here
            int y = clientOriginOnDisplay.y + clientArea.height - popupSize.y - padding;

            popupShell.setLocation(x, y);
        };

        parentShell.addListener(SWT.Move, moveListener);
        parentShell.addListener(SWT.Resize, moveListener);

        popupShell.addListener(SWT.Dispose, e -> {
            if (!parentShell.isDisposed()) {
                parentShell.removeListener(SWT.Move, moveListener);
                parentShell.removeListener(SWT.Resize, moveListener);
            }
        });
    }