When using Object navigation in various dialog boxes in Office, for instance the font dialog (control+d) or modify style dialog in Word (control+shift+s to open "apply styles" then tab to "Modify" and press enter), only some objects are accessible.

Initially I was trying to navigate around the modify keystroke dialog from the modify style dialog because when you enter a keystroke to assign to a style, there is a text label which notes whether the keys you have pressed are "Currently assigned to" anything else. (press control+shift+s to open apply styles, then tab to modify and enter, then press alt+o for format and k for shortcut key).