This tool toggles the parental relationship between one or more designated bones (typically target bones) and a "Root" bone - taking into account the designated bones existing keyframed translation animation. Allowing you to localise the designated bones (reparent them to "Root"), before editing or reanimating the "Root" bones' movement, then setting the designated bones back to their original unparented globally positioned state.
This tool & technique can be used to contain or isolate a characters existing movement & animation (typically those that use unparented Target bones) - such that the character can be made to run/walk/jump/animate 'on the spot' - as might be required for Sprite animation or similar.

Example A: After removing X translation of the "root" bone
Howto (typical use):
- Select one or more Target bones (can be any bone - but typically target & unparented)
- Click (run) the 'Toggle Parent Bone' tool to: Attach the selected bones to the "root" bone and adjust their transforms to make them relative to "root" (*1)
- (optionally) Review the new Parent relationship using the standard reparent bone tool
- Add/Edit/Remove any desired "Root" bone movement (*4)
- ReSelect the Target bones
- Click (run) the 'Toggle Parent Bone' tool to: Detach the selected bones from the "root" bone and adjust their transforms to make them global again
- Review the new animation

Example B: After removing X translation of the "root" bone
Notes:
There are a few caveats with this (v1.0) release:
1) The tool currently assumes the "Root" bone to be the first defined bone (top of bone list is Select Bone drop down). You don't actually need to reparent to the actual root bone for this to work, but any bone that moves inline with root should work OK
2) The animation may look funny / broken when Target bones go from Global to Local (parented), but should be OK again once you toggle them back
3) The tool only attempts to target/fix the translation of selected Target bones
4) I have found that animations seem to rework best - when the "Root" bone Y transforms are unchanged and X is removed/altered (with Separated Dimensions). Your requirements & mileage may vary
5) A dialog for Root/Parent selection is planned
6) ** The tool will ignore & ultimately remove any existing re-parenting keyframes on the selected target bones
The tool can be downloaded here: ss-moho-toggle-parent-bone.zip