In Impress, and by default, the Text Formatting toolbar is not visible. But when you click some object (e.g. to start typing text into it) - the formatting toolbar becomes visible. When you click outside the object (e.g. on the slide background) - the formatting toolbar disappears.

But now suppose, that I want the Text Formatting toolbar on all the time. Legitimate, right? So, on the menus, I set View | Toolbars | Text Formatting to be checked. However - the behavior described above doesn't change. That is, with the toolbar already visible, clicking on some object keeps it just the way it is, but when you click outside the object - the Text Formatting toolbar disappears.

This is a bug.

The same thing happens with the Table toolbar, w.r.t. clicking on tables; and perhaps elsewhere.