Tip: Uncaught Invariant Violation

> Uncaught Invariant Violation: onlyChild must be passed a children with exactly one child. Are you using Reagent and Bootstrap with ClojureScript, and getting this error? In my case, the cause was that I had a when inside an OverlayTrigger. Seems like a no-no. Further testing showed you can't have an if either. Looks like OverlayTrigger can only wrap data, not something that might change. In my case the solution was simple enough, once I figured out the cause: I just extracted when to wrap the OverlayTrigger, instead of the other way around.