Sierra + Thunderbird Email + Window Server = High CPU
 

I experience very high CPU (100% in Activity Monitor) when I run either Thunderbird or Firefox and have the application window appear on the DisplayLink driven monitor, even if the applications is idle.

I found an earlier note suggested turning off the option to use hardware acceleration when available. Most of the time this does reduce the cpu, but I still experience certain situations that cause the CPU to spike again.

One repeatable example is when Thunderbird is displaying status. I can turn off the status line, but I was wondering if there are any other ways to prevent this type of behavior.

My Configuration as follows:
Macbook Pro Late 2011 17" 2.5 GHZ
Sierra 10.12.6
Display Link Driver 4.3.172 and previous 4.1 release
USB3.0 UHD DisplayPort Adapter:
OWC Thunderbolt 2 Dock (for USB 3.0)
Thunderbird 52.9.1
Firefox 62.0