Is there a way in the wing debugger to say "if a variable ever != 0 break"

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Unfortunately not directly, due to the very large overhead this would add, if checking the value after each byte code. For things like properties you can set a breakpoint in the method that sets it, or in methods like __setitem__. Also, if there is a good place to put it, adding 'assert myvar == 0' to code might work.