Searching and filtering are different features and perform different functions.
A search will start with nothing and will find events that match the search criteria you entered, and return them as a list of results. Results can be found that are outside your current view and are not affected by the number of days you have in view. Search starts with an empty results list and adds to it.
Filters will always start with your main view and take information away from the dates you are viewing to leave you with only the events and resources that match your filter. Filters start with your view and takes unwanted information away.