I create simple example and try scale yellow rectangle:
The yellow rectangle is obtained by duplicating the green. Moved and filled with pattern..
When I press the Shift+S (Scale), I expect that scaling will be from center of this rectangle, but in my case center of scaling start from a center of canvas rectangle. How to scale with ignoring transparent part of canvas? Something like here:
Or if this isn't Gimp's case behavior please recommend right way for Gimp.