The last bone here, Bone7, has an ik constraint of chain length 3. As in the image, moving ikBone moves the bones all the way back to bone4. This makes me think that the length of a chain doesn't include the first bone, Bone7. Or that the counting starts at zero.
I want to limit the rotation of Bone4, the last bone in that chain.
I think that ik overrides Limit Rotation bone constraints and the way to achieve the result I want is via the Inverse Kinematics tab, found in the bone properties as described here
Those constraints work ok for Bone6 & Bone5, the 1st & 2nd bones in the chain. Here are the constraint fields for bone 5.
The problem comes with Bone4, the final bone in the chain. Looking at that same constraint panel for Bone4, the fields are greyed out.
Although greyed, values can be entered in the fields and the check boxes can still be checked. Setting up various test situations, for reasons unknown to me, sometimes the Bone4 ik constraints are enforced and othertimes not.
So my question is, what is the significance of the fields being greyed and in what circumstances are those constraints enforced?
Blender v2.83.0 on Linux