It more or less is the same base (just they throw in a lot of extra package, and some tools of their own).
If or if not they actually have patches to the IDE itself => I don't know.
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I tested with 4.99 and switching of that hint, did not disable the completion.
The completion can be controlled in the codetool settings "Identifier completion".
Though, if memory servers (not 100% sure) it uses the same timer as the hint.
Which means if you changed the delay for the hint (rather than disable it by the checkbox), then you may (probably) also have changed the delay for the code completion.