Clicking on any rocket part in Construction mode in VAB (except pods) has double click/possible automatic "root"

[C128user]

I have not played KSP for many months because I have been frustrated by a bug that appeared after upgrading to 1.12 (and even the latest patch, 1.12.3).  When I go to construct a rocket in the VAB, clicking on any object you can add to a rocket causes the Root mode to be activated, and a double click is heard.  The Parent button also appears below the editor gizmos.  This does not happen for any "pods" (capsules, probes, etc).  I know it is not my mouse, as in numerous other programs it does not double click in error, and a spurious "4" does not show up when typing in any other program so it is not the keyboard.  This did not happen until I updated to 1.12.

I can post particulars of my system specs if needed.  Since I have run in sandbox mode and not in career mode.  I am considering a complete uninstall and reinstall (removing save files as well), but I would like to hear some opinions of what is happening before going to that drastic step.  I also got a free Making History DLC from Private Division for "upgrading" my account with them, and I would like to run with that.

[jimmymcgoochie]

Can you post screenshots or a video of the problem? Which of the four buttons in the top-left is highlighted when you select a part to add to the craft? Can you actually attach the parts OK or is there something preventing that?

From my brief testing in KSP 1.12.3 with no mods, selecting any part from the list will automatically set it to "place" mode and set the symmetry mode to "parent", while in many cases it seems to play the click sound twice with a very short delay between the two clicks. I've noticed this apparent double click in heavily modded copies of the game where it can take a couple of seconds between clicking the part and the part actually appearing, it's completely harmless and you can safely ignore it.