WKWebViewControlMBS shouldPerformDownload always false

I’m using WKWEbViewControlMBS as a browser. When the user clicks on a download link I’m trying to trap that in the decidePolicyForNavigationAction event --navigationAction.shouldPerformDownload should indicate if a download should happen. But regardless of what download links I click, navigationAction.shouldPerformDownload is always false. Has anyone gotten this to work?

I’ve used that control, and have noticed that some of the default values didn’t always match what I expected - in my case, it was probably due to me changing the superclass of an existing HTMLViewer, which wiped out defaults. See MBS WebView2 Experiences - #3 by Mike_D (Edit to clarify: we are talking about 2 different controls, but the underlying issue may be the same - if you change a control’s super in the IDE, the defaults settings may be lost. This may have nothing to do with the issue you are seeing, however!)