I have created a macro and tested it (it runs correctly) from Tools → Macros → Run Macro
This is in Writer.
I go to Tools → Customize → Keyboard to assign the key. I have chosen Shift-F12.
When I select the key, the Modify button is enabled and I can assign any normal command to it. But when I scroll down the left hand Category column, as soon as I select the LibreOffice macros item, the Modify button goes grey, and is no longer usable. So, what is going on? All help I can find about assigning macros to keys says this is the correct procedure.
What am I overlooking, this is really maddening.