@morrow without logs this will be hard to track down. can you ask your administrator to open up a support case for this?
To make life easier for power users, the 1.2 version of the Zarafa WebApp debuts with a new innovative tab bar. This tab bar is placed on top of the message list and reading pane and enables users to switch quickly between several opened emails, but also new emails that are in progress and other items like contacts or calendar items. With this new way of tabbing, opened emails are no longer stacked on top of each other and power users do not have to organize pop-ups again and again to have a clear overview. Once a tab is selected it will be displayed full screen.
WebApp is Zarafa’s enterprise collaboration web client for home and general office usage. This next-generation client not only features basic functionality such as email, calendaring, meeting requests and tasks, it also includes multi-calendaring and advanced delegation via the browser. Thanks to the strongly integrated API of the WebApp, plug-ins can be developed easily and quickly. In this way, user driven innovation enables enterprises to remain aligned with future collaboration developments. People using WebApp already benefit from plug-ins that vary from chat, web meetings and Dropbox to Twitter.
The Zarafa WebApp can be installed as an additional package from Zarafa Collaboration Platform 7.0.8 and 7.1.0 and higher.