Mail preview does not fill the screen in Zimbra Web Client 8.x and Google Chrome

When Google Chrome released a new version on 2 September 2015, Zimbra Web Client versions 8.6, 8.5, and 8.0 began displaying the mail preview incorrectly: it did not fill the screen. This problem occurred on every OS, including Mac, Linux, and Windows, as shown below.

Manual workaround

1. Edit the file:

   /opt/zimbra/jetty-distribution-7.6.12.v20130726/webapps/zimbra/skins/_base/base2/skin.css 
   /opt/zimbra/jetty-distribution-7.6.12.v20130726/webapps/zimbra/skins/_base/base3/skin.css 

   Search for the classes below and check whether they match. If they do, skip to the next step. Otherwise, change them to match first.

   
   #skin_td_sidebar_ad             {  width:@SidebarAdWidth@;  }
   #skin_container_sidebar_ad      {  @AdStyle@ width:@SidebarAdWidth@;  }

2. Find the class named skin_td_main, as in this example: #skin_td_main { width:auto; height:100%; } Change it to match the following:

   #skin_td_main > TABLE {
     table-layout: fixed;
   }

3. After making the change, restart the mailbox service with: zmmailboxdctl restart

Automatic script workaround

1. Download the script with: wget https://raw.githubusercontent.com/jorgedlcruz/Zimbra/master/Zimbra%20Google%20Chrome%2045%20Fix/zimbra-chrome45-fix.sh
2. Set its permissions to allow execution: chmod +x zimbra-chrome45-fix.sh
3. Run the script: sh zimbra-chrome45-fix.sh
4. Restart the mailbox service: zmmailboxdctl restart

Ref: Zimbra Wiki