Building VSIX doesn't use changed files.

[ngzero]

I don't know if Code Snippet Studio caches the content of the snippets or if an existing vsix file can't be replaced, but if I change a snippet, open vsix and click build vsix, the package contains the old snippet. I've seen this behavior concrete while changing the keyword of a snippet.

[AlessandroDelSole]

If I understand fine, you aren't telling Studio to update your snippet in the .vsix, so what you should do is:

1. Open the existing .vsix
2. In the snippet list, remove the old snippet and add the new one (I agree that I should implement replacement at this point)
3. Build the .vsix again

[ngzero]

I've already done this and it works. It was just suggestion for replacement :)