The function add-variable-watcher registers a callback that is invoked whenever the variable’s value changes. You could use it to save old values in a list or other data structure.

It’s not my intention to be condescending. However, using a 25 year old piece of software that is not being maintained anymore is rarely the best option. You didn’t explain why you can’t use a newer version of Windows or a modern Linux distro.

Why don’t you just use a modern version of Windows? You can download it from Microsoft for free. It only lacks a few non-essential features without activation.

That’s what I call an informative title.

Ivy and Helm do not support repeating arbitrary completion sessions in full generality - because it is hardly possible. Only the state of commands which go through the ivy-read or helm API can be fully reconstructed.

They do for commands that are defined with the ivy and helm framework. The downside of course is that everything has to be rewritten using their frameworks in order to have first class support. This is also necessary if you want other features such as actions and is one of the biggest disadvantages of using them.

One of the strengths of vertico is its modularity and compatibility with builtin APIs. Unfortunately, this also makes it difficult to restore a vertico session because vertico does not have access to the full completion state in the way that more monolithic completion packages like helm and ivy do. Some of it might even be created through a series of function calls which would be hard to reconstruct.

I would guess that vertico is not always able to repeat extended commands properly and so they are disabled by default. Unfortunately, vertico-repeat is fairly limited. Check out this post for more information. https://www.reddit.com/r/emacs/s/TV1Asbrhel

Minad (the vertico author) made some attempts at a better repeat extension but they all have various limitations. I ended up making my own repeat extension but it had issues as well so I’ve since abandoned it.

Unfortunately, if you must have such a feature in full generality, I’d recommend that you use helm or ivy instead. Personally, I’ve just learned to live with it as the advantages of the vertico stack are worth it IMO.

What is the difference between the vanilla and GNU versions?

I haven’t usedlsp-mode with JavaScript. However, the first thing to try is to check if there is an alternative server that might be faster. This makes a big difference for some languages.