In SQL Server Reporting Services (SSRS), the toolbar that displays the report controls and export features, appears on multiple lines when viewed with Internet Explorer 11.

In my search of a fix, I came across the following: 
https://connect.microsoft.com/SQLServer/feedback/details/810527/sql-server-reporting-services-is-not-compatible-with-internet-explorer-11

In the post I found the following from Mariusz Cichomski of Microsoft.

Hello

We are happy to inform that the problem was fixed in CU8 for SQL Server 2012 Sp1. Please visit the http://support.microsoft.com/kb/2917531 to get the update.

Mariusz Cichomski Program Manager 
SQL Server, Microsoft