Can't switch tabs after iheart.com stream is playing for a while

[Yuri]

I am not sure whether this is FreeBSD specific issue or not, but here 
are steps to reproduce it:
1. go to www.ktrh.com
2. click blue triangle (play button)
3. iheart.com/#/live/2285/?autoplay=true tab will show up and will play 
audio.
4. after few hours of playing I am not able to switch tabs any more.

When I click on some tab, it's title gets to the window title, but tab 
itself doesn't become active.

I see this on FreeBSD-8.2 on the current port version 16.0.912.63, and 
not on Ubuntu 15.0.874.106.

Yuri