IK Influence slider pops itself back to zero (WTF?)

I’m working with a very well-rigged figure armature (not by me), which has constraints set up for the hand bones. The IK constraints are set to zero Influence by default, and when I set the slider to 1, the hand bone follows its influence bone just fine.


When I move the mouse away from the Influence slider and out of the button window, the slider visibly pops back to 0.0 on its own. I’ve been able to duplicate this repeatedly, and it happens before my very eyes. The armature in the 3D window stays in the position it would be at when the Influence is set to zero, but as soon as I rotate the view, the figure pops back to the zero-influence position, on its own.

So as it stands, I can’t activate the influence of these IK constraints.

Am I missing something here? This is Blender 2.49b running on Windows XP Pro SP3.

Well, here I am 12 years later looking for answer lol. I ended up inserted key in the influence slider to get it fixed, not sure what’s happening.