batch modify tasks

I don't know if I should post this as an idea or a problem. It can fit under either category.
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There are situation where I need to modify a bunch of tasks all in the same way.

For instance, if I have an unexpected bump in the road on a project and all the tasks (could be hundreds!) have to slip 3 days. I really need a way to change the due date of selected tasks all at once.

I hope this isn't too difficult to implement, and I hope it can be given a somewhat high priority as the need is immediate, important and ongoing.

Thanks.
- Bal