Keith,
Thank you for your interest in MyEclipse. I am afraid it is not clear where exactly the auto complete fails in the files you sent.
CodeMix is not compatible with MyEclipse 2021 and can no longer be installed on it as MyEclipse 2021 already has in-built support. The editors in MyEclipse 2021 are based on Language Server tech. Capabilities like validation, content assist, navigation are serviced by the Language Server protocol.
If you are seeing issues with auto complete, then please recheck if the JS files are opened with JavaScript :: Language Server
editor (Right click on the file in the Explorer view > Open with). If you are still seeing problems, then please share the exact details of where it fails, which file etc (screenshots would be great) to help us replicate the issue at our end.
–Swapna
Genuitec Support