I thought it was a preferences setting, but instead it appears to be a setting in UBoot.
In my AmigaOS4 system partition I have a drawer called "Documentation", which contains many interesting things including some info on Keyboards.
Here is a quote from Documentation/Keyboards.doc ...
VII) If your PS/2 keyboard switcher (KVM) reacts on ScrollLock
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keyboard.device V50.10 and higher for A1 can use the PrintScreen/SysReq
key as Help key (instead of ScrollLock) if you set the UBoot variable
"kbddev_sysreqishelp" to either "1" or "yes". Then AmigaOS will ignore
the ScrollLock key.
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redfox