If you add a Custom Filter via the Filter Gramplet, then the list of "Filters" pop-up menu in the Filter Parameters tool is updated.
But, if you create a Custom Filter from the pop-up contextual menu of a Clipboard object (add a Person to the Clipboard, select them on the Clipboard, right-click that selected Person on the clipboard, choose "Create Filter from the Person selected...", rename filter & save), then Filter Parameters "Filters:" menu does not show the new Custom Filter.
Found another edge case bug.
If you add a Custom Filter via the Filter Gramplet, then the list of "Filters" pop-up menu in the Filter Parameters tool is updated.
But, if you create a Custom Filter from the pop-up contextual menu of a Clipboard object (add a Person to the Clipboard, select them on the Clipboard, right-click that selected Person on the clipboard, choose "Create Filter from the Person selected...", rename filter & save), then Filter Parameters "Filters:" menu does not show the new Custom Filter.
The built-in Filter Editor isn't updated either. Worse, that built-in tool rewrites the truncated list and flushes the Clipboard created filter.