When the user types a value in a grid column filter, clicks the filter button, then deletes the value from the column filter, and clicks the filter button, the grid results will not change to reflect the updated filter. When the filter text is removed, and the filter button is clicked, the grid results should be updated.
I agree, The filter should act at least one of the ways below when filter textbox is empty 1. Click "Filter" will reset the filter (function same as Clear Filter button) 2. "Filter" button is disabled when there is no input 3. Click "Filter" will do nothing, but the filter menu will stay open and have error indicator to let user know nothing isn't a valid filter criteria. At very least, if user open the filter menu again, the filter input box should keep the last valid search expression.