This is a bug that has managed to evade its due squashing for quite some time. Like you said, restarting Poser is a workaround. Though I've found a lot of times you can get the properties panel to refresh with the correct parameters if press the numbers 1, 2, 3 a few times. (the numbers above the letters/under the f keys...not the num pad on the right) 1 selects element (body parts/props) 2 selects figure 3 selects camera so try selecting the body part then hitting 2, 3, 1. If that doesn't work then def restarts. Its annoying but ive got around this for ages. (hope they fix it one day)

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My most recent Poser animation:
Previs Dummies 2