Using only keystrokes the Special Characters dialog box will insert the character, but will not activate the Insert choice as it does when using a mouse. I tried every activation key combo I knew without getting the Insert box to activate so I could "properly" exit the dialog. However, on ESC out of the dialog box, I found I had inserted numerous instances of the character I sought to use.
During keyboard navigation (cursor R L U D) within the character chart, the focus is already placed on the 'Insert' button. Meaning, to place the selected char--just press the 'Enter' key. Special Character Dialog then closes. There is no keyboard multi-character picks to document, that requires use of mouse and double-mouse click selections--and 'Cancel' or 'X' to close the dialog after picks. WFM => NAB