Thanks for the post and for the detailed steps to reproduce this - appreciate the time you took here.
I am following your steps - on both Windows and Mac OS - but I’m unable to see what you are seeing. In my case, all mockups appear and the “Link to Web Address…” and other options also appear:
Which version of Mockups 3 are you using? You can check in “About Balsamiq Mockups” (“Help” menu in Windows or “Balsamiq Mockups 3” on OSX.
The latest version is 3.5.15. If you’re not using that version, would you download (https://balsamiq.com/download/) and install that version and let me know if the issue persists? Either way, get back to us and we’ll get to the bottom of this for you, ok?
All the best,