Returning from sleep will re-enable disabled monitor

[and-rea]

Hello, I have this current setup:

• MacOS 10.11.5
• iMac (21.5-inch, Late 2009) monitor disabled
• secondary monitor (BenQ GW2765) attached by DisplayPort, enabled and set as primary

When monitor returns from sleep, the iMac monitor is no longer disabled, and I need to disable it again manually.

[reagle]

Yes, this significantly decreases its utility as my monitor sleeps often.