comment.block.documentation custom autocomplete (misbehavior, crash)

I have some custom auto-completions set up for documentation comments. Example:
{
    "scope": "comment.block.documentation",
    "completions":
    [
        { "trigger" : "@access",     "contents": "@access ${1:accesstype}" }
    ]
}

The problem is that, though showing up in the suggestions list correctly after i type in "@acc" and press Ctrl+Enter, I can only insert the corresponding snippet by pressing tab, while all other snippets are insertable with Enter key. `tab_completion` setting doesn't seem to affect anything. To makes matters worse, if the option is selected from suggestions list with a mouse, ST may even crash (it happened once so far, under WindowsXP, but I could not reproduce the crash), or just do nothing.

As a side note, automatic suggestions do not work in documentation  comments.