Currently, except if it is due to a misconfiguration on my side, I am not seeing any code completion for keywords in official libraries. For instance, I would expect the following
*** Settings ***
Library Screenshot
*** Test Cases ***
Test
Take [cursor here]
when pressing ctrl+space to propose the two possible completions, Take Screenshot and Take Screenshot Without Embedding (as seen there).
Similarly, when importing self-made libraries (either in python or in java), I would expect the auto-complete to work there also.
I realise that this would be a big undertaking, but it would really go a long way to make the plugin really useful for mixed projects - because sometimes, it is just not possible to define all keywords with Robot Framework directly.