Elm Visual Bug caused by "Active" filter.

[Ahmet Ayrancioglu]

When a todo item is marked as completed while the show active filter is selected, the item below shows the checkmark by mistake.

To replicate:

1. Create a todo task named "do1"
2. Create a todo task named "do2"
3. Change the filter to show "Active"
4. Mark do1 as completed
5. Observe the checkmark next to "do2"

Changing the filter to "All" and then to "Active" shows the correct state.