Not getting an expected ThreadAccessingUI exception

Working on my main app, I ran it to test some changes I made, expecting to see a file selection dialog box appear. What actually happened is that it became unresponsive (and with no CPU usage) and I had to force-quit it (macOS, 10.13.6). Thinking about it I realised I’d asked a thread to do:

[code]Dim dlg As OpenDialog, inputf As FolderItem

dlg = New OpenDialog
dlg.Title = “Select an image file”
inputf = dlg.ShowModal

which, ISTM, ought to give me a ThreadAccessingUI exception. But it doesn’t; it hangs instead. Is this a bug? I have a tiny project I can submit with a Feedback case if so.

I’ll be moving this sequence onto the main thread, evidently.

Yes, that seems like it should raise a ThreadAccessingUIException, please file a case.