I learned something from Wikihelp today:

  1. In the drawing area, right-click a dimension lock.
  2. Select Show Related from the context menu. The appropriate element highlights and a dialog identifies the element.
  3. Click the arrow buttons to switch between the elements constrained by the lock.

From:
Distinguishing a Dimension Lock’s Related Element – WikiHelp
via
https://twitter.com/RevitWikiHelp