Command suggestions don't work!
What I expected to happen was...:
When I pressed the / button and typed, there were supposed to be suggestions.
What actually happened was...:
No suggestions popped up!
Steps to Reproduce:
No steps really needed here...
Are you in a single-player world with cheats disabled, or on a server without operator privilege? Hitting / and then tab should have a result, but if you have started typing a command you don't have access to it will give the behaviour you describe. I can't reproduce this with 1.14.2-pre2 on windows 10 and java 1.8.0_201