Purpose of user setting WorkPathChanged ?

Hi all,

I have started to look at 
https://bugs.documentfoundation.org/show_bug.cgi?id=43021.

It is about Windows and therefore the method setDisplayDirectory from 
/core/fpicker/source/win32/filepicker/VistaFilePicker.cxx is involved.

I know already, that if the property PROP_FORCE is set to "true", the 
directory is set in the file picker. But simple forcing it to "true" has 
problems in other parts, where a file picker is used. So I need some 
deeper understanding. And in that I struggle about "WorkPathChanged".

The method setDisplayDirectory sets the user setting WorkPathChanged to 
"false". From the UI I see that it is set to "true", if you change the 
"My Documents" path in Tools>Options. But I do not find the place where 
this setting is evaluated.

And it makes no sense to me, that the method setDisplayDirectory changes 
a user setting, because the API says, "Sets the directory that the file 
dialog initially displays." and nothing else.

Kind regards
Regina