This is an idea and not a defect. I think it would be very nice if we could select multiple task lines on a Schedule to, for example, mass delete them and to change the task mode for selected tasks my mass selecting them. Please see attached image. This would make cerating templates a lot faster.

Imagine if you make a 100 task WBS and want to change the task modes on all tasks. Mass edit would be incredibly fast as opposed to indicidually selecting every single task.