I have the latest Fedora 26 installed with konqueror-17.04.1-1.fc26.x86_64. In this version, there is no option to use the FileManager view. I can start Konqueror as a File Manager by opening my home folder as a url. However, there is no File System Tree SideBar. Pressing F9 as we did in the past is not working too.
*** This bug has been marked as a duplicate of bug 373824 ***