With the introduction of subtasks, it would be interesting to have the option to select both completed and incomplete items.

The scenario is this. Lets say you are doing a small project. Set it up as a task, with sub tasks.

Currently you have to flip between completed and incomplete to see all the tasks. If you could select all, you get to see roughly how far through the project you are. Just different colours, or a line striking through the completed tasks would be ideal.