It is a known issue with IE11 and above for vCenter Server 5.x & 5.5 vCenter Server 5.1 Update 2 Release Note, However with vSphere 6, you shouldn't be facing this issue.
It is a known issue with IE11 and above for vCenter Server 5.x & 5.5 vCenter Server 5.1 Update 2 Release Note, However with vSphere 6, you shouldn't be facing this issue.