armin_sheikh When multiple physics constraints are selected, the bone section becomes hidden:
This is expected behavior. To change the constrained bone, select a single physics constraint.
To elaborate further, this behavior—where selecting multiple constraints hides some or all properties—is consistent throughout Spine. The same applies to other types of constraints, such as transform constraints. For example, when multiple transform constraints are selected, the Bones and Target fields are hidden, and only the remaining properties are displayed.
This design is intentional. It is common to want to toggle options or adjust mix values for multiple constraints at once, but since most constraints control different bones, keeping fields that are not meaningful to share across multiple constraints visible could easily lead to mistakes. To prevent such operational errors, these fields are hidden when multiple constraints are selected.
