Fighting with autocompletion

Hello,
I am literally stuck with a weird autocompletion issue: I have to fight the editor to undo autocompletion, and the editor is currently winning. In the video, I am using arrows to navigate, backspace and delete, ctrl+z to undo the insertion of “]”.
atom
Has anyone experienced anything similar? Any idea how to fix this?

Here is the list of the packages installed.
atom-bracket-highlight
autocomplete-plus
document-outline
git-diff-details
git-log
git-time-machine
highlight-selected
indent-detective
ink
julia-client
language-julia
language-latex
language-todo
latex
latex-autocomplete
latex-completions
latexer
latex-hyperclick
minimap
minimap-find-and-replace
minimap-git-diff
minimap-highlight-selected
pdf-view
platformio-ide-terminal
project-manager
svn
todo-show
tool-bar
uber-juno

Does it still happen if you disable this?

Turn off your packages until it stops happening. Since Atom doesn’t have any native support for LaTeX, we know for a fact that it’s one of your packages. If you take the problem systematically, you will ignore everything that isn’t LaTeX-specific and start looking for snippets or autocomplete packages that might be causing it. In this case, I did that for you and found that latexer is causing the completion in a way that completely bypasses the standard autocomplete system (which is why you don’t see a drop-down).

I’ve had similar issues with latexer before. Try disabling it.

A less destructive solution (assuming @kva has a use for latexer) would be to disable the setting that tells the package to run its environment completion function.

(In case it’s not clear, you do that in Settings, not in the code. I’m just pointing at where it is in the code to show you that it’s there because I don’t have the package installed.)

latexer was at fault