I'm not sure what "showerror" is; I don't see it anywhere in the Python built-in functions or the Poser API. But this kind of behavior is common, especially when using the TKinter setup. Python is rather clumsy about claiming the Active Window or the keyboard Focus. For instance, when I do a "raise" command in Python, which is supposed to print an error message in a separate box, the box sometimes appears at the right time, sometimes appears only after the TKinter frame is closed, sometimes appears with no contents but fills in the contents after the Python task is closed.

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