I've disabled auto completion of {} from the advanced settings menu, but the program still automatically adds a ] when I type [ in examples like:
\item[--]
Is this a bug or can I disable it some other way?
[Tex/LaTex] Disable TeXstudio auto completion of square brackets
auto-completionbracketstexstudio
Related Solutions
Please uncheck "Auto Complete Parentheses". It can be found "Options / configure TeXStudio" (see screenshot). It does work for me under TeXStudio 2.12.14.
Edit: as for the shortcut CTRL+I. I don't think there is an easy way to achieve that. You will have to either alter an existing cwl file (where the definitions are stored) or create a new one. Perhaps you can find an answer when you search for the term "custom cwl".
The easiest way is to tell TeXstudio to suggest the Most used commands you enter: Menu > Options > Configure > Completion > [Preferred Commands Set] select 'Most Used'.
Other than that, you can create your own .cwl set for TeXStudio to use.
Best Answer
For the case you've given
]is inserted, because\item[text]is in the completer. Once you've typed\item[this is the only possible choice in the completer. You may disable this by uncheckingConfigure -> Completion -> Autocomplete Common Prefix.