www.wysiwygwebbuilder.com

Just installed v19 (64-bit), entered my registration key, went through options, added my Open AI API key, and...nothing. All the AI menu items are grayed out.

Is there another step to get this working?

Did you read the tutorial?
https://www.wysiwygwebbuilder.com/ai.html

The AI tools in the Ribbon are active when you are in text edit mode or if you have selected an image.
In other cases, the tools are available via the context menu. where text or an image can be inserted.

You did restart the application after entering it? Or your computer?

Read the tutorial three times. Rebooted the PC and the app multiple times. Whitelisted WB19 in my anti-virus (both the app and the folder). I'm not using the ribbon, but when I go to Format > Artificial Intelligence, all the selections are grayed out. Same with Edit > Artificial Intelligence (except the prompt editor is available).

I even went to Open AI and generated a second API key. Also tried launching WB19 as administrator. No joy.

Missing a step somewhere...

Text
Edit -> Artificial Intelligence
Did you go into text edit mode (double click text)?

Images
Format -> Artificial Intelligence
Did you select an image?

or
Insert -> Image -> Image create with AI

However, if I do as Pablo suggests: Insert > Image > image create with AI, it works. The Format > Artificial Intelligence remains unavailable.

Did you select an image? Otherwise the image tool will not be enabled.

Note: whether or not the tools are enabled does not depend on the API key. The tools are context sensitive, so they are enabled based on the current selection.

Okay, got it sorted. As usual: operator error.

Thanks, guys!

I can understand that it may be confusing.
I think the main problem here is that standard menu (unlike the Ribbon) is not context sensitive. So, there are multiple 'Artificial Intelligence' items, one for text and one for image, because they trigger different commands.
When using the Ribbon, the correct AI tools are visible when they can be used.