Safari macOS: Unable to restore the Interface Viewer from the Dock

Problem

When you use the Highlight/Auto-Highlight feature in the Interface Viewer to highlight web controls running on Safari macOS, the Viewer automatically minimizes itself to an icon on the Dock. However, clicking on the icon in the Dock fails to restore the minimized Viewer.

Solution

Deactivate the Minimized windows into application icon option by doing the following:
  1. Open the Dock's preferences settings by selecting Apple menu > System Preferences, and then clicking Dock.
  2. Clear the Minimized windows into application icon check box.
  3. Restart the Interface Viewer.