How to change the default open issues view?

[FG Bee]

Currently, we are opening tasks and then assigning sub-tasks to them to indicate work necessary to complete the task itself.  The default Open Issues screen lists all of the tasks and sub-tasks in the Issues list, jumbles together  I would like Open Issues to ONLY show the Tasks.  This way, the sub-tasks are only visible in the detail view pane when you click on the appropriate task.