task list becomes gittery when show completed task is turned on

### What Happened?

When you add new tasks and turn on show completed tasks and tick the box to complete a task the list starting jumping up and down.

### Steps to Reproduce

1. add two new task with time data filled in.
2. enable show completed tasks.
3. tick any one of them

### Expected Behavior

it shouldn't jump.

### OS Version

7.x (Horus)

### Session Type

Classic Session (X11, This is the default)

### Software Version

Latest release (I have run all updates)

### Log Output

_No response_

### Hardware Info

_No response_