Hi, to reproduce, run demodemo as you have done, and then click/tap the Stream test button. When the new window appears, start to move your graphical cursor over it and it will throw the error.
I observed that this is now happening with at least several other of the demodemo test applications, and it was happening in my private application as well, which I have not yet released, on multiple computers. I haven't done much research into the exact cause of the problem, as in my mind it was more of an excuse to request an update to the latest release of mcclim. -- Christopher Howard