if (!isWindowAlphaSupported()) {
throw new UnsupportedOperationException("Set sun.java2d.noddraw=true to enable transparent windows");
}
whenDisplayable(w, new Runnable() {
public void run() {
HWND hWnd = getHWnd(w);
User32 user = User32.INSTANCE;
int flags = user.GetWindowLong(hWnd, User32.GWL_EXSTYLE);
byte level = (byte)((int)(255 * alpha) & 0xFF);
if (usingUpdateLayeredWindow(w)) {
// If already using UpdateLayeredWindow, continue to