WebClient does not mark read mail "read state" until "Get New button" clicked.

Installed newest 12.1.1.0:

IceWarpServer-12.1.1_x64.exe   985,555,288   2018/6/4   11:04:00AM
(ftp://dl.icewarp.com/server/Windows/icewarp12)

Confirmed on Firefox, Google Chrome, IE 11, Opera, WebClient does not mark opened/read mail(s) as read state, unless manually click "Get New" (Refresh) button, those opened/read mails are marked as read.

BR,

Jason