The text expand icons can show up for many reasons.
Most likely it's because there is hidden text or formatting that while you can't see it, is affecting the number of characters it takes for Captivate to detect that there is too much text to display. There could be formatting, or a series of extra line breaks that at a glance you don't see but are there. Edit the text for these elements and press CTRL+A to select and highlight the text. You will quite clearly see extra line breaks if that's it. When adding text always either make sure you paste it in without formatting or use a tool like PureText to strip out any formatting from Microsoft Office or wherever you are copying your text from.
Another reason they show up is that you've applied an effect to these items such as an Ease-In or something like that. This is bug and you should take the time to report it.
It doesn't look like it in this case, but some fonts use up way more space than the visible character itself. I don't think this is the case, because that looks like Trebuchet MS, but something to be aware of
Thanks so much, Paul! The weird thing is this slide has been working fine and just started showing these boxes. Thanks for telling me about the update, which I did. I noticed that the project now has fluid boxes even though I was using breakpoints. I switched the project to breakpoints and the text is working correctly now...no new boxes. Why would the project change to fluid boxes on it's own. Have you ever heard of that? Thanks again!
Oh also check for updates to Adobe Captivate 2017. There was an update a few weeks back that hasn't been applied to your copy of Captivate. I know this because the text expand icons have changed color since then. The update includes bug fixes that will help you out in other ways as well.
Small explanation about 'Preferences' and 'Cache'.
The Cache is meant to be able to re-open a project quicker, and in case of serious trouble, a cached folder can sometimes function as an ultimate backup (hope you enabled the normal backup setting in Preferences). Since CP folders can be very heavy, the cache folder will quickly grow sometimes to huge size. It is a good idea to clear the cache regularly. If you do it with the button in Preferences, only the cache of non-open projects will be cleared. I also have an AIR app that allows me to choose the caches to be cleared, have no idea if it is still available. Not dangerous!
Clearing the Preferences is only needed when you suspect that Captivate is corrupting (not an individual file), starts behaving weirdly. It means that some customisation settings will be lost. I have blogged about it on my personal blog, how to recover those custom items. Will not post a link or this answer will have to wait for moderation.
Hi! Thanks again for your quick and informative response. No, I did not set up normal backup setting in Preferences. I did not know about that. I googled and don't see the term "normal backup," but I do see Generate Project Backup, which I did not have checked. Is that what you mean? Also, thanks for explaining the difference between cache and preferences....now it's much less scary!
Please turn on Project Backup. That is the first step in any basic training I offer. It should be checked off by default, but my feature request concerning that never made it.
Wished the Help documentation was a little bit more up to date....
Thank you so much. Huge help!