Second screen wallpaper has wrong menu bar size
My primary monitor has the proper menu bar set, but my secondary screen is always black when using the --all-displays option. I've tried every possible combination of monitor settings to make it work.
Try a different wallpaper file for the second display. And post the output to see if there is some error.
Not sure I am experiencing the same bug or a slightly different one but for me the main display works but the second display goes half of whatever color I set. There doesn't appear to be any error. Version 0.8.0.
./ChangeMenuBarColor SolidColor "#000" --all-displays
Starting up
Using currently set macOS wallpaper file:///Users/aaronraimist/Library/Application%20Support/ChangeMenuBarColor/wallpaper-screen-adjusted-B2B48599-FB1D-45F1-A3FD-0F6A7BDC3862.jpg
Generating solid color image
Created new wallpaper for the main screen in file:///Users/aaronraimist/Library/Application%20Support/ChangeMenuBarColor//wallpaper-screen-adjusted-9986545A-D7BE-4972-99F5-38035BD153BA.jpg
Wallpaper set
Using currently set macOS wallpaper file:///System/Library/Desktop%20Pictures/Big%20Sur%20Road.heic
Generating solid color image
Created new wallpaper for the main screen in file:///Users/aaronraimist/Library/Application%20Support/ChangeMenuBarColor//wallpaper-screen-adjusted-5A2038EE-C902-40F1-AAEA-74FEDFE2AFA2.jpg
Wallpaper set
All done!
./ChangeMenuBarColor SolidColor "#f70018" --all-displays
Starting up
Using currently set macOS wallpaper file:///Users/aaronraimist/Library/Application%20Support/ChangeMenuBarColor//wallpaper-screen-adjusted-ECFD6C5E-BEC6-4F14-A825-21588ED14C25.jpg
Generating solid color image
Created new wallpaper for the main screen in file:///Users/aaronraimist/Library/Application%20Support/ChangeMenuBarColor//wallpaper-screen-adjusted-ACBB295A-61AD-4DF7-B194-E77BA9447B5D.jpg
Wallpaper set
Using currently set macOS wallpaper file:///Users/aaronraimist/Library/Application%20Support/ChangeMenuBarColor//wallpaper-screen-adjusted-91BE7322-61FE-4F62-886C-3E73B14633F0.jpg
Generating solid color image
Created new wallpaper for the main screen in file:///Users/aaronraimist/Library/Application%20Support/ChangeMenuBarColor//wallpaper-screen-adjusted-FE6B8AD0-DA29-4A33-AFC1-8F2525A8E307.jpg
Wallpaper set
All done!
Have same issue. Using external monitor 2560 × 1440 px. When I set wallpaper (using static, stock one) and use ChangeMenuBarColor SolidColor "#CCCCCC" --all-displays I’m getting wallpaper with overlay color way too big on the external screen (internal screen is OK).

same issue