If the dim is linked then it has a name. If you look in the equations folder in the feature tree you will see all linked dims there. One easy way to see what it may be linked to is to right click on the annotations folder in the feature tree and select the option to show feature dimensions. Once you have done this to see then maes of the dimensions if you will click on the glasses (hide/show items) in the heads up view toolbar select the option to show dimension names (looks like D1). Then look for a dim with the same name.