Mark Formatting Inconsistencies

Check your Options

What this task pane actually shows depends on two important settings on the Edit tab of your (Tools > Options).

Keep track of formatting - (Added in 2002). Select this check box to allow Word to keep track of, or store, formatting information as you type, so that you can easily apply it elsewhere.
Mark formatting inconsistencies - (Added in 2002). Marks formatting with wavy, blue underlines when it is similar, but not exactly the same, as other formatting in your document. Word can identify direct formatting that's similar to formatting you've applied more frequently, list formatting that's similar to other list formatting, and direct formatting that matches a style. To use this option, the Keep track of formatting check box must also be selected.
For the rest of this page lets assume that both of these options are checked.