1. Make sure there's a text object in the current slide.

2. Unselect all objects.

3. Add a contextual toolbar, like View/Toolbars/Line and filling, and put it in its own row (i.e. not in the same row as an existing toolbar).

4. Click inside the text object to edit it.

The Line and Filling toolbar disappears, since it is not valid for the text editing context.  However, this causes the entire slide view to change zoom.  This is very disorienting, as it changes *again* when you are finished editing the object.

The slide view should stay at a fixed position and zoom factor.  If a toolbar is out of context, just disable its items temporarily.