Curve Editor Pop-out Closes on Modification

The internal curve editor closes its popout window automatically on any modification, which makes it difficult to use to edit the curve.

See also the attached video demonstrating the bug

1. Double click on an FRuntimeFloatCurve property in the details panel to popout the curve editor
2. In the context menu, select "add key"
3. The popout window closes itself unexpectedly
4. Bring out the popout window again
5. Drag the key node to around
6. The popout window closes itself again