When you are coding in Studio, it is very common that the intellisense box will pop-up, which you would normally just immediately press enter to have it auto-fill the first entry. However what happens is that the box will disappear, stutter, and then re-appear. You can then press enter to have it fill in your desired text.
This issue plagues development.
Expected behavior
Intellisense box appears, you press enter, it fills in the desired text.
We have just flipped a flag that should fix this issue after a Studio restart. Please let us know if you continue to see this problem.
Regrettably the fix flag caused a performance regression and had to be backed out. We are working on further improvements and will reach out with an update when possible.
The bug in which Autocomplete disappears/flickers when attempting to accept, rather than actually accepting, should be fixed in the latest version of Studio for the Script Editor use-case (it currently persists in the Command Bar because of differences in how the two editor front-ends handle text updates). If you can still reproduce this issue in the Script Editor I would be very interested to hear it.
As for autocomplete being slow to resolve - this is a bit harder to address as it’s not just a single bug. Autocomplete is ultimately powered by the Luau type system, so the longer the script takes to typecheck, the longer autocomplete results will take. We have a few ideas for improving this performance, which we are actively working on, but without a repro case it is difficult to know if it will improve your particular place.