Does anyone have a solution for this problem?
I have a form with a string field for storing a full file name.

The lookup works fine but does not give me the path only the file name:

I have tried a couple of code variants with the same result:
public static FileName getFileBrowse()
{
Filename fileName;
FileUploadResultBase fileUpload;
fileUpload = File::GetFileFromUser() as FileUploadResultBase;
fileName = fileUpload.getFileName();
return fileName;
}
public static fileName getFileBrowseDialog(FilePath _filePath, str _fileTypesAccepted)
{
System.IO.Stream stream;
FileUploadBuild fileUpload;
DialogGroup dlgUploadGroup;
FileUploadBuild fileUploadBuild;
FormBuildControl formBuildControl;
Dialog dialog = new Dialog('Get file');
DialogField dialogFilename;
Filename filename;
dialog.filenameLookupInitialPath(_filePath);
dlgUploadGroup = dialog.addGroup('File name');
formBuildControl = dialog.formBuildDesign().control(dlgUploadGroup.name());
fileUploadBuild = formBuildControl.addControlEx(classstr(FileUpload), 'Upload');
fileUploadBuild.style(FileUploadStyle::MinimalWithFilename);
fileUploadBuild.fileTypesAccepted(_fileTypesAccepted);
if (dialog.run() && dialog.closedOk())
{
FileUpload fileUploadControl = dialog.formRun().control(dialog.formRun().controlId('Upload'));
FileUploadTemporaryStorageResult fileUploadResult = fileUploadControl.getFileUploadResult() as FileUploadTemporaryStorageResult;
filename = fileUploadControl.dataRelationPath(fileUploadControl.fileName());
return filename;
}