Crash rebuilding TableListBox/ListBox

I have a ListBox and a TableListBox in a component that’s used as a preset browser. When I rebuild the browser before it’s visible and then display it, it works fine every time. But I also have a Refresh button in the browser and when I push that, calling the same rebuild code, I sometimes crash in MessageManager::runDispatchLoop() :

libc++abi.dylib: terminating with uncaught exception of type std::length_error: vector

Obviously, I’m doing something stupid, but I can’t seem to find it and not sure how to debug this.

Any ideas? Thank you,.