Hi JWeaver,
It sounds as though the view has Highlight Filters enabled. Choose View >
More Views to show the More Views dialog box. The view should be selected
already, click the Edit button to show the View Definition dialog box.
In the View Definition dialog box, uncheck Highlight Filter. Click OK to
close the View Definition dialog box. Click Close to close the More Views
Dialog box.
Try running the filter from the Filter list in the Formatting toolbar and it
should work as you wanted, hiding the tasks that do not meet the criteria.
I hope this helps. Let us know how you get along.
Julie