It's because Tab accepts copilot suggestion, you have to press Enter instead to accept the language server suggestion.
Intellisense + Intellicode + Roslynator (extension) combined were really the height of productivity in Visual Studio. Now they've driven a steam-roller over all of that, forced CoPilot down our throats.
I LIKE CoPilot's "chat" interface, and agents are fine too (although Claude in VS Code is tons better), but CoPilot auto-complete is negative value and shouldn't be used.
What would be nice is if you could ask for a suggestion with one key, so it's there when I want it, and not when I don't. That would put me in control. Instead I feel subjected to these completely random whims of the AI.
Otoh I disabled all the intellisense stuff so I don't have the issues described in TFA: tab is always copilot autocomplete for whatever it shows in grey.
Why can't all the suggestions come through the same UI element? That's beyond my understanding.
You'd get suggestions from,
- multiple language servers
- matches from the same buffer/project or sibling pane (tab,window, whatever you call it)
- matches from the dictionary