Thanks! Follow-up question: is there a way to edit the keyword list (e.g. delete keywords)?
Not directly, as the Keywords list in the Filter is a simple list of all the keywords applied to some or all of the images source (e.g. All Photos, or a folder or an individual album), and is not editable. But it's still easy enough to do:
Let's assume you want to delete a keyword from all images in the library, so click on All Photos to make that the source for the filter and make sure you are in one of the Grid modes. Then click on the Filter icon and select Keywords, then scroll down to find the keyword you want to delete. When you've found it, click on it....that will repopulate the grid with only those images which contain that specific keyword. Now Cmd+A to select all those images, then click on the Keyword icon at the bottom of the right-hand toolbar, which will open the right-hand panel to show the People & Keywords panel. At the top will be all the people that have been identified in the selected images, scroll down to the Keywords section.....this will typically be in two section: "Applied to All" (at the top), and "Applied to Some" below. The keyword you are trying to delete will be in the top "Applied to All" section, and if you hover over that keyword you will see the text will turn red with a line through it (i.e. indicates that if you click on it, the keyword will be deleted). So to delete it, click on it while it's in that red state.
It's quicker to do than to type.