[GH-ISSUE #243] One monitor doesn't update when when using 2 external monitors #189

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opened 2026-05-05 05:22:12 -06:00 by gitea-mirror · 3 comments

gitea-mirror commented

2026-05-05 05:22:12 -06:00

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Originally created by @MarkEstefanos on GitHub (Jun 19, 2020).
Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/243

Checklist

I have searched for existing issues
I have looked through the wiki
I have updated MonitorControl to the latest version

Describe the bug
When using 2 identical external monitors, the sliders for both monitors only effect the first monitor, with neither slider ever effecting for the second monitor.

If I check "Change Brightness/Volume for all screens" the second monitor doesn't change at all when I change the brightness

When using only 1 monitor at a time everything works as expected with either monitor.

To Reproduce
Steps to reproduce the behavior:

Plug in both monitors.
Run MonitorControl.
Attempt to change the brightness on either.

Expected behavior
Each slider would effect its respective monitor.

Screenshots

Additional context

Environment Information (please complete the following information):

macOS version: 10.15.5
MonitorControl version: 2.0.0
Monitor(s): 2x BENQ BL2711U
Both using mini-DP to HDMI adapters

Originally created by @MarkEstefanos on GitHub (Jun 19, 2020). Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/243 **Checklist** - [x] I have searched for existing issues - [x] I have looked through [the wiki](https://github.com/MonitorControl/MonitorControl/wiki) - [x] I have updated MonitorControl to the latest version **Describe the bug** When using 2 identical external monitors, the sliders for both monitors only effect the first monitor, with neither slider ever effecting for the second monitor. If I check "Change Brightness/Volume for all screens" the second monitor doesn't change at all when I change the brightness When using only 1 monitor at a time everything works as expected with either monitor. **To Reproduce** Steps to reproduce the behavior: 1. Plug in both monitors. 2. Run MonitorControl. 3. Attempt to change the brightness on either. **Expected behavior** Each slider would effect its respective monitor. **Screenshots** **Additional context** **Environment Information (please complete the following information):** - macOS version: 10.15.5 - MonitorControl version: 2.0.0 - Monitor(s): 2x BENQ BL2711U Both using mini-DP to HDMI adapters

gitea-mirror

2026-05-05 05:22:12 -06:00

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gitea-mirror referenced this issue

2026-05-05 05:22:19 -06:00

[GH-ISSUE #241] Option to hide the menubar icon #188

gitea-mirror commented

2026-05-05 05:22:20 -06:00

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@MarkEstefanos commented on GitHub (Jun 19, 2020):

Same issue with ddcctl.

./ddcctl -d 1 -b 35
and
./ddcctl -d 2 -b 35

both effect only the first external monitor. I also tried digging around the source of MonitorControl a bit to see if I could isolate the bug, but no luck so far.

@MarkEstefanos commented on GitHub (Jun 19, 2020): Same issue with ddcctl. `./ddcctl -d 1 -b 35` and `./ddcctl -d 2 -b 35` both effect only the first external monitor. I also tried digging around the source of MonitorControl a bit to see if I could isolate the bug, but no luck so far.

gitea-mirror commented

2026-05-05 05:22:21 -06:00

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@MarkEstefanos commented on GitHub (Jun 19, 2020):

Looks like this is the bug I'm running into: https://github.com/kfix/ddcctl/issues/17

@MarkEstefanos commented on GitHub (Jun 19, 2020): Looks like this is the bug I'm running into: https://github.com/kfix/ddcctl/issues/17

gitea-mirror commented

2026-05-05 05:22:24 -06:00

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@JoniVR commented on GitHub (Jun 19, 2020):

Duplicate of #49

@JoniVR commented on GitHub (Jun 19, 2020): Duplicate of #49

gitea-mirror referenced this issue

2026-05-05 05:40:19 -06:00

[GH-ISSUE #346] Menu Bar Icon #276