When clicking tab after typing "/fill ~ ~ ~ ~1 ~1 ~1 minecraft:air 0 replace" and clicking tab after "replace", clicking tab will not autofill the blank space after replace, which can be set.
When clicking tab after typing "/fill ~ ~ ~ ~1 ~1 ~1 minecraft:air 0 replace" and clicking tab after "replace", clicking tab will not autofill the blank space after replace, which can be set.
Working as intended.
Before all optional parameters tab won't place a blank., you have to type it by yourself to indicate that you want to use the optional parameter.