WebDriverException in dismiss_alert()

New to SST, so this could be operator error. I'm getting a WebDriverException when I do a dismiss_alert() or accept_alert(). If I wrap the dismiss_alert() in a try/except, the alert is dismissed and the test runs fine.

HTML fragment:
  <input type="button" id="aaa_button" value="click"
      onclick="alert('aaa button pressed'); return false;"
  />

SST fragment:
  click_element('aaa_button', wait=False)
  dismiss_alert()

Traceback is below.

I'd be glad to raise a bug if this looks like an SST bug and not a newbie bug :)

Thanks.

  -- Jeff

======================================================================
ERROR: test_SST_aaa (sst.runtests.TestSst_Aaa)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Python26\lib\site-packages\sst\runtests.py", line 260, in test
    exec self.code in context
  File "C:\Zope\aps.um.buildout.20110315\parts\inst1\Products\APSUM\tests\SST\SS
T_aaa.py", line 19, in <module>
    dismiss_alert()
  File "C:\Python26\lib\site-packages\sst\actions.py", line 1049, in dismiss_ale
rt
    _alert_action('dismiss', expected_text, text_to_write)
  File "C:\Python26\lib\site-packages\sst\actions.py", line 1001, in _alert_acti
on
    window_handle = browser.current_window_handle
  File "C:\Python26\lib\site-packages\selenium\webdriver\remote\webdriver.py", l
ine 455, in current_window_handle
    return self.execute(Command.GET_CURRENT_WINDOW_HANDLE)['value']
  File "C:\Python26\lib\site-packages\selenium\webdriver\remote\webdriver.py", l
ine 153, in execute
    self.error_handler.check_response(response)
  File "C:\Python26\lib\site-packages\selenium\webdriver\remote\errorhandler.py"
, line 147, in check_response
    raise exception_class(message, screen, stacktrace)
WebDriverException: Message: u'Modal dialog present'