how do you set autogroup triggers on no file buffers?

I'm using a plugin which always creates a buffer named "[Scratch]" whenever I use omnicomplete. I want to hide this. I tried doing this:

au BufNew [Scratch] bunload

However, this never gets triggered. I believe that is because the pattern is matching against the filename and not the buffer name. Is there a way to to change this behavior?

EDIT:

Never mind, the option I wanted was

set completeopt = menu,menuone,longest

This gets rid of the scra开发者_C百科tch buffer.

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This looks like the wrong approach.

Instead I'll look into the (omnicomplete?) plugin you are using to see if there is an option to disable the creation of that scratch buffer. If not, contact the plugin's author to ask him to add this option.