After performing the update that was released yesterday to assure compatibility with El Capitan, unfortunately certain dialog boxes still appear as shown in the screen shot below. It was captured while debugging a script on a layout in table view.
I wish I could tell you what they say. I suspect things like progress bars that tell users to wait for sorts, replace, relookup, etc. But that is just a wild guess. I saw this when I was using El Capitan prior to the 14.0.3 update but I hoped the problem would disappear after 14.0.3 was released.
I do not see this problem when using Windows 10 in Parallels.