InitialDirectory does not appear to be implemented

[SeanE63]

I am initializing the BrowserProperties as shown:

 var bp = new BrowserProperties
 {
 initialDir = sMap.ModulePath,
 title = "Load Module",
 filter = "Module files (*txt)| *txt",
 filterIndex = 0
 };
 
 then calling the FileBrowser().OpenFileBrowser. It doesn't matter what directory I hand for initialDir, the browser opens up in the last directory it was open in.