I mostly use the todo-list for items that have multiple "sub-parts". It could be 5, 7, 13, 17, 24 - nearly any number between 2 and 25. What I think could be useful, both for me and many others, is a field in the "new task" window that allows to enter how many "sub-parts" the item has. And then, if the subparts-field is activated, the "in progress"-menu will allow select how many parts that are done directly, and the progress bar percentage are calculated. Let's say I have an item with 7 subparts, then the "in progress"-menu would say "0/7, 1/7, 2/7, and so on", instead of 0%, 10%, and so on.

What do you think about this?

The problem adding these kind of non-standard features is that if the iCalendar format doesn't support them they will break the compatibility with other calendar applications. This doesn't mean that such features couldn't be added but there needs to be enough demand for them.

But wouldn't the progress still be "stored"/saved as percentage? If I've done 3 of 7 parts, it could calculate that that is 43% - I'm just suggesting that the progress menu could be in custom intervals - not 0, 10, 20% - to match the appropriate number of sub-parts..

Ah ok, so you are just suggesting a new field to the editor where you can set the sub-part count. I was thinking more of a hierarchical subtasks which would be tied to the main task. I'm not too keen on adding new stuff to the editor dialog since it's quite cluttered already but I'll think about it.

Yeah, yeah. What I'm imaging is a little checkbox to tick and a small field to enter a number. And then, if checked and if 4 were entered, the "in progress" pop-up menu will have these options: "0%, 25%, 50%, 75%, 100%". If 9 were entered, it will have "0%, 11%, 22%, 33%, ... 88%, 100%". So that the number of sub-parts entered in that field decides which values that are available in the "in progress" menu.