Rearrange playlists/regions?

Hi, and thanks for Ardour!

I want to remix/rearrange a song.
I want to rearrange an ABCD song sequence into ABCBD
I import the wav files into Ardour (v2.8.1)
I choose Splice mode.
And my Edit Point is Mouse.
I drag-select section B with the mouse and choose Convert to Region in-place.
I Select the newly created Region B and Ctrl-drag it further down the timeline and drop at the point between sections C and D.
But now I have a blank period of silence equal to the length of Region-copy B before the newly dropped region, ie. it goes ABCBD ( is blank/silence).
And the newly dropped region-copy B is silent, ie. mute, as well.

Any help appreciated!