"move to archive" keeps disappearing from the new email window

I have a Gmail account set up on EM Client. when I receive a new email and click on the mail icon on taskbar the app opens it in a new window. when I’m done with it, I want to archive it. by default there is no “move to archive” thing on the head bar. so I right click on the head bar >> customize >> and then add “move to archive” to the right column which is “items to show”. 
The problem is it only shows one time, every time I got a new email, the “move to archive” item is hidden again despite showing it on the customize screen. see the screenshot of the problem. 

Hello Amir,

Thank you for contacting us, we’re sorry that you’re experiencing this issue. We’re however aware of this bug and it will be fixed in the future version.

Thank you for your patience,