On the Context Filtering tab of a script deployment record, you can select the contexts in which you want your script to execute. Your script will not execute if it is triggered in a context that is not selected. By default, all contexts are selected except for Web Application and Web Store. Often, it is not required to trigger scripts in these contexts, so they are disabled by default to improve performance. If you want your script to be triggered in these contexts, be sure to select them explicitly when you create your script deployment record.