I discovered a very easy, albeit crude, solution to the popup (pop-up) mouse-over text balloon (I'm piling on the key words here) problem. I wanted a text box (which I could format) to appear if I hovered over particular areas on slide.

1. I simply copied the entire slide to another slide and then added the desired text box to the copied slide.

2. I selected the text (could be an object) and then added an Action Setting, selecting mouseover and the slide that I had created the extra text box on.

3. I then went to the target textbox and created its own Action Setting with a mouseover that would take you back to the original slide.

4. Repeat as necessary for additional text boxes (that is, each box requires its own duplicated slide, so this is a very inefficient work-around).

5. Then I created an object (rectangle) as big as the original slide, with no fill and no line, moved it to the back, and gave it an action setting so that clicking anywhere in the slide would jump me to the next "real" slide in the sequence.

Wallah. Awkward, stupid, functional.