In File Manager all file type icons are shown as question marks in CentOS6 and CentOS7 Containers. CentOS5 Containers are OK.
File Manager functionality is provided by System Administrator Control Panel application.
To get file types File Manager uses
/usr/bin/file command which is included in CentOS5 but is absent in CentOS6 and CentOS7.
SACP is obsolete and replaced with Virtuozzo Power Panel. Power Panel is shown as Parallels Power Panel in OBAS interface up to 4.5.5 release. Starting from 4.5.6 the Panel is shown as Virtuozzo Power Panel.