Default file manager and folder associations

[Jacopo De Simoi]

Dear kcd, 
  
  I am thinking for a possible fix for bug #293576 [1], but I could not make 
up my mind so far. As far as I understand the situation is as follows: 

- There is no explicit way of setting the default file manager for the KDE 
workspace; however, there is an implicit way of doing that by selecting the 
desired program as the default file association for folders. 

- When the user adds a new file association by 

rightclick > open with... > other + tick “remember file association”

the newly added program is set as default for the corresponding mimetype.

This two behaviors together sum up to bug 293576: a user wants to open a 
folder with a random program (that is VLC in the br); he therefore adds the 
corresponding action via the rightclick business described above. This selects 
VLC as the default file association for folders, and forces applications to 
believe that VLC is our default file manager.

In particular the device notifier is easily fooled by this situation, and 
opens every device with vlc :( 
The reporter was kind enough to document this with a video [2]

So far I came up with a couple of solutions, but all do require some feedback:

1) Create an explicit way to set the default file manager (which might or 
might not necessarily be the default association for folders) so that the user 
cannot change it without noticing. 
2) “Protect” folders as a special type of file and disallow to set a random 
application as default unless explicitly requested using the kcm

My first thought was that this was really a corner usecase, and it very 
possibly is; however, I must admit that this behavior is indeed quite bizarre 
(please do have a look at the video) and, unless you really know what is going 
on, it does seems to make little or no sense at all.

Other solutions are of course most welcome. 
Thanks,

  Jacopo

[1] http://bugs.kde.org/show_bug.cgi?id=293576
[2] http://www.youtube.com/watch?v=tPQaUKIBwCc