[lmi] Meaning of wxFLP_FILE_MUST_EXIST

[Greg Chicares]

Using lmi HEAD, I can enter a nonexistent file in this control:

  <object class="wxFilePickerCtrl" name="DefaultInputFilename">
    
<style>wxFLP_OPEN|wxFLP_FILE_MUST_EXIST|wxFLP_USE_TEXTCTRL|wxFLP_SMALL</style>
                      ^^^^^^^^^^^^^^^^^^^^^

and it's accepted--and I like that behavior, because I can
manually type the name of a nonexistent file in order to have
no custom default. I do however think the wx documentation
  http://docs.wxwidgets.org/3.0/classwx_file_picker_ctrl.html
could be improved.

It says
| wxFLP_FILE_MUST_EXIST:
| Can be combined with wxFLP_OPEN only: the selected file must be an existing 
file.
which isn't necessarily wrong if "selected" means picked in
the popup. It wouldn't hurt to mention that a nonexisting file
name can always be manually typed into the managed text control
(when wxFLP_USE_TEXTCTRL is specified), and will be accepted.

Then it also says
| void wxFilePickerCtrl::SetPath(const wxString & filename)     
| Sets the absolute path of the currently selected file.
| This must be a valid file if the wxFLP_FILE_MUST_EXIST style was given.
I think the last sentence is incorrect and should be deleted.
This lmi code calls SetPath():

    bool Transfer(transfer_direction td, std::string& data, wxFilePickerCtrl& 
control)
    {
        if(td == from_string_to_control)
            {
            control.SetPath(data);
            }

and it successfully passes the nonexistent filename I enter.

I would strongly prefer that the code not change. I'm only
saying that the documentation could describe it better.