I have simple scripts to turn down the brightness of my MacBook via an AppleScript. This worked fine in Catalina 10.15.3, but has stopped working after I upgraded to 10.15.4.
The script is as follows:
tell application "System Preferences"
reveal anchor "displaysDisplayTab" of pane "com.apple.preference.displays"
end tell
tell application "System Events" to tell process "System Preferences" to tell window "Built-in Retina Display"
set value of value indicator 1 of slider 1 of group 1 of tab group 1 to 0.0
end tell
..error is as follows:
error "System Events got an error: Can’t get slider 1 of group 1 of tab group 1 of window
\"Built-in Retina Display\" of process \"System Preferences\". Invalid index." number -1719
from slider 1 of group 1 of tab group 1 of window "Built-in Retina Display" of process "System Preferences"