The BookmarkImage property indicates the index of the icon to show a bookmark on the link. Use the Images method to insert icons to the control. The ImageSize property defines the size (width/height) of the icons within the control's Images collection. Use the BookMarkBackColor and BookMarkBackColor2 properties to customize colors of the control's bookmark bar. The BookmarkWidth property shows or hides the bookmark bar on the control. The BookmarkBorderColor property specifies the color to show the border of the bookmark bar. The user can bookmark/un-bookmark a line within the control by pressing the CTRL + F2 key. You can navigate through the control' bookmarks using the F2 or Shift + F2 key.