java.awt.Robot.waitForIdle() unrealiable

We are seeing frequent timing issues in our nightly UI tests. The tests often fail because events performed by the java.awt.Robot have not completed before the test code tries to verifying the results.

We are code like using:

Point p = cb.getLocationOnScreen();
int m = 5;
if (cb.getWidth()<5||cb.getHeight()<5)
    m=3;
System.out.println("Click at " + (p.x+m) + "," + (p.y+m));
robot.mouseMove(p.x + m, p.y + m);
robot.mousePress(MouseEvent.BUTTON1_MASK);
robot.mouseRelease(MouseEvent.BUTTON1_MASK);
robot.waitForIdle();
Thread.sleep(100);
// Verify results...

We keep having the bump up the Thread.sleep to ensure things complete on the event thread (things like clicking on a button or typing text) despite the java.awt.Robot.waitForIdle() call.

I found this question (Does java.awt.Robot.waitForIdle() wait for events to be dispatched?) which says to use java.awt.Toolkit.realSync(), but this is not an accessible method and with Java 9 coming, I'd rather not add any unnecessary reflection to our tests.

Are there better solutions? Or do people use realSync() or just increase the wait time until tests pass reliably?