The ability to disable Calculation (it goes for IK/Connections and Physics) is created for the situation you describe: the ability to make various changes with being interrupted every time by the Solver.
You disable calculation by clicking the button, make the necessary changes, and enable calculation again and eventually execute one of both ‘Precalculate’ commands. The satutus enabled/disabled is indicated by a red cross over the button.
In my experience at this phase of development (and probably even later) it would be interesting to know whether Precalculation is OK or not. Especially when the model misbehaves one often has doubts. I guess that is what is bothering you.
There is a list of events that set the status of Precalculation “dirty” (meaning ‘needs to be done over’). Then there is a list of event that evoke Precalulation, like manipulapting the timeline slider, click Play etc…. I am pretty sure both lists are not exhaustive. Please @Joshua correct me if I’m wrong.
Your traffic light idea above inspires me to a status coloring:
Red: Calculation is executed but failed.
Orange: Calculation is “dirty” and needs to be done over
Green: Calculation is successfully executed.
Even when calculation is disabled this status coloring can be upheld (maybe the corss should be a bitt larger).
When there are no IK Joints or Connections, or no Physic enabled objects obviously the status is omitted.
What do you think?