[QFileSystemWatcher]Signal directoryChanged not emitted when deleting a subdirectory under windows 10

Hi,
I have tested with my app synchro (built again with Qt5.6.2). at the beginning of the app all the child paths of the directory watched are added recursevely and when a new directory is added the path is added.so the watcher watches all the paths.But when deleting a subdirectory (that is watched and not shift+del) under windows 10 the signal directoryChanged is not emitted for this deleted directory.I upload my app Synchro built with Qt5.6.2 (mingw4.9.2 of the site qt.io -release version)
this app is for test purposes and the class is used in another app that we want to publish (fast finished)