If you set AutoPostBackOnFilter property of a column to True, the user does not need to press the filter button to initiate filtering. Instead, a postback filter operation occurs when the user types a filter in the filter box and presses [Enter] from the keyboard. Hence what you face is an expected behavior, since pressing [Enter] makes a postback.
Yes I understand that. What's happening is if I hit tab or lose focus in anyway it runs the filter. The issue is when I hit enter it runs the filter, and the. Runs a complete page post back. The grid is ajaxified so all all other fields when I hit enter it refreshes just the grid, when I tab off of any of the filter boxes it refreshes the grid, but when I hit enter on the to date box and only the to date box it will refresh the grid, and the it runs a complete page reload which sets the grid back to the original state.