I think this is a nice improvement. Two questions.

1. When the addition of a component is undone, should the parent of that component be selected by default? For example, with a new design, I add a nose cone and close, then undo adding the nose cone. Should the sustainer be selected so that I don't have to select the sustainer before adding a new/different component at that level? Or, with a new design, I add a body tube and close, then add an inner tube and close, then undo the inner tube. Should the body tube be selected so that I don't have to select the body tube before adding a new/different component at that level?
2. Is this sufficiently related to Issue 960 such that the two should be combined (the undo function here would have the same function as the cancel button in that issue New feature request: add ok/cancel button to component config dialog #960)?

Functions as expected, no anomalies found.

Build 787
[Windows 11 Pro; Version 21H2; OS Build 22000.739; Windows Feature Experience Pack 1000.22000.739.0]
[Java "11.0.15" 2022-04-19 LTS; Java(TM) SE Runtime Environment 18.9 (build 11.0.15+8-LTS-149)]

I like this change.

1. When the addition of a component is undone, should the parent of that component be selected by default? For example, with a new design, I add a nose cone and close, then undo adding the nose cone. Should the sustainer be selected so that I don't have to select the sustainer before adding a new/different component at that level? Or, with a new design, I add a body tube and close, then add an inner tube and close, then undo the inner tube. Should the body tube be selected so that I don't have to select the body tube before adding a new/different component at that level?

Could be a good new feature request (so will not be solved in this PR).

2. Is this sufficiently related to Issue 960 such that the two should be combined (the undo function here would have the same function as the cancel button in that issue

Not really a solution for #960, I just meant that with this functionality, it will be easier to implement a fix for #960.