Removing styles safely

[Ulodesk]

Removing styles can be a tricky business in a long document, especially one with imported tables. Reviewing this issue the other day, I realized that I don't understand the style pane options in recent versions.



In 2010, if I create a document and add text in nothing but the Normal style, and I have made no style changes or additions, right clicking on a style in the styles pane brings up a list that includes "Remove all (No data)", "Select all (No data)", and "Delete [style name]", which is grayed out for Normal.

However, after adding a style, the pop-up list includes, instead, "Select all x instances", "Clear formatting of all x instances", and still ""Delete [style name]". In the case of a style that has not been used, "(Not currently used)" appears, grayed out.

The one aspect I don't understand is the "(No data)" tag. At first I assumed it to mean that no data in the document was styled this way and, therefore, the style could be deleted without concern. However, a colleague the other day had a lengthy document with a number of styles (or was it, perhaps, just formatting?) which yielded the tag, and he did delete the styles. I don't know what happened.

What does this tag mean, under what curcimstances does it appear, and how should it be treated?