Expand canvas - choose canvas extension colour

[Don - NZ]

Please allow us to set the canvas extension colour - with defaults for black, white, foreground, background and custom colours.  I was able to work around this even in a macro, but it would have been so much simpler just to be able to tick, say, black in a dialogue box.

 

[KnikmanAV]

and the same for a negative crop (extension of the image) to create a border around an image