When command suggestions are disabled, pressing Tab doesn't insert the first suggestion into chat

auto-complete needs to press the tab key twice to make it work. I find it annoying having to press tab twice to have auto completetion.

  example:
  to write the command "/gamemode creative" in 1.13.

  /ga [Tab] [Tab]
  /gamemode c [Tab] [Tab]
  /gamemode creative [enter]

To reproduce this bug

1. go to option "chat settings" -----> "command suggestion: Off"
2. start writing a command
3. use [tab] for autocompletion