Consider the following scenario:
You sign in to Microsoft Lync 2013.
In the Lync –Options dialog box, you select the Enable tabbed conversations check box in the General tab.
You start multiple conversations.
You try to switch between the conversation windows by pressing CTRL+TAB.
In this scenario, CTRL+TAB does not work.
To resolve this issue, install the following update:
2880474 Description of the Lync 2013 update: April 2014