Currently in the Gantt View, if you have 2 dependent tasks -the first task with a 1 day duration and the second task with a 3 day duration- and close the first task, the progress percentage will be 50% regardless of the tasks duration, since the progress percentage in the Gantt View is calculated by tasks completed divided by the total tasks in the group.

But sometimes is more useful to know the progress percentage based on the duration of the tasks, this way when you close the first task in the given example, the progress percentage will be 25% (1 out of 4 days completed).

Therefore, I propose that the Gantt View have the option of choosing between these two ways of calculating the progress percentage -the task quantity based calculation (currently available) and the task duration based calculation (the proposed way).