it's happening every-time
That's very strange indeed. We tried to reproduce this behavior in our test systems, but everything seems to be fine. Maybe you can try cleaning Mannequin's user preferences?
To do this, open C:\Users\[yourusername]\AppData\Roaming\Mannequin and then delete both user-preferences.json and user-preferences-dev.json (if this file also exists).
Let us know more if there's further problems.