This is sort of a tl;dr ticket for http://code.google.com/p/selenium/issues/detail?id=3075
, but:

The following code:


      profile = Selenium::WebDriver::Firefox::Profile.new
      # See http://code.google.com/p/selenium/issues/detail?id=3154
      profile['toolkit.telemetry.prompted'] = 2
      profile['toolkit.telemetry.rejected'] = true

      caps = Selenium::WebDriver::Remote::Capabilities.firefox(:firefox_profile =>
profile)
      @driver = Selenium::WebDriver.for( :remote,  :url => "http://localhost:#{@port}/wd/hub",
                                        :desired_capabilities => caps)


causes firefox to run without native events.  This code uses native events:


      @driver = Selenium::WebDriver.for( :remote,  :url => "http://localhost:#{@port}/wd/hub",
                                        :desired_capabilities => @browser.to_sym )


As does this:


      profile = Selenium::WebDriver::Firefox::Profile.new
      print "profile: #{profile.inspect}\n"
      # See http://code.google.com/p/selenium/issues/detail?id=3154
      profile['toolkit.telemetry.prompted'] = '2'
      profile['toolkit.telemetry.rejected'] = 'true'
      profile.native_events = true
      print "profile: #{profile.inspect}\n"

      caps = Selenium::WebDriver::Remote::Capabilities.firefox(:firefox_profile =>
profile,
                                                               :browser_name      
   => "firefox",
                                                               :javascript_enabled
   => true,
                                                               :takes_screenshot  
   => true,
                                                               :css_selectors_enabled
=> true,
                                                               :native_events     
   => true
                                                              )
      @driver = Selenium::WebDriver.for( :remote,  :url => "http://localhost:#{@port}/wd/hub",
                                        :desired_capabilities => caps)


Note that in that last one, the important line is " profile.native_events = true";
with that commented out, things break again.

So, apparently Selenium::WebDriver::Firefox::Profile.new defaults to native events
off, but having no profile with the remote driver defaults to them on.  That is, to
put it mildly, *surprising*, especially since there's no obvious indicator as to whether
we're in native event mode or not.

-Robin