Re-docking a task pane

Hello,

Using Excel 365, I've double clicked on my task pane to reposition it, and now when trying to re-dock the task pane, I've tried to double click the title, but it won't re-dock to the default position.

Any idea why this is happening? And, is there a way to get it to it's default position?

Thank you!
Robert

Task Pane.png