To speed up formatting table borders, add a control in or near the proxy control (where you click on lines to select or deselect corresponding borders of the selected table region) to enable quickly selecting all of the borders or none of the borders.

Also, increase the contrast between the blue and gray colors used for the proxy lines as it is sometimes hard to tell the difference between them. Currently their values are almost identical (appx 60% black). Suggest lightening up the gray "unselected" color to 25-30% black.