The Markup > Draw > Hot Spot command places a hot spot in the currently active markup layer. Click to place one
corner of the rectangle, and then drag the mouse to place the opposite corner.
Hot spots will appear either as a rectangle with a lightning bolt through it or as a filled rectangle, as determined on the General tab of the Markup Options dialog box.
Double-click on a hot spot to display the linked image or file.
This command is available only when a markup layer is open in the current file.