Question about captive portal problem

[Ties Jan Hefting <tj hefting net>]

Hello all!

First of all: thanks for all the hard work of the Network Manager. It 
makes networking as easy as pie! :)

I have a problem with the captive portal and I think I should direct my 
questions to this mailing list. If not, please let me know who/where I 
should ask about this. ;)

In my country there is free WiFi in a lot of trains. It uses a captive 
portal, which is detected perfectly and shows the web authentication 
window to login. To login I only have to tick a tickbox and click a 
button. However, when I click this button, nothing happens. So, I close 
the window and go in Firefox to the captive portal manually, and there 
the button works.

One thing I noticed is that it opens a new window/tab after I've logged 
in successfully. If I take a look at the source code, this button 
submits a form using JavaScript. The form only consists of the 
beforementioned tickbox. In the 'form' tag the 'target' attribute is set 
to 'connectiontarget', but I can't find that elsewhere in the source 
code, nor do I know what the HTML spec says about this non-standard 
value. I know that my Android smartphone handles this well, while there 
seems to be no distinction between desktop and mobile in the login page, 
so I think it's the same web page.

Screenshots can be found here: http://imgur.com/a/BfmYF

My questions are:
1. Is there a log file I can take a look at to find out what's going 
wrong here?
2. Is this a known problem? If so, is there a solution/workaround?
3. If this is unexpected behaviour, where can I file a bug report on 
this?

Thanks in advance,
TJ