Select→Move Idiom in GIMP

GIMP is extremely powerful for a cross-platform free image manipulation software, but it has some... oddities. The most fundamental oddity is the lack of the select→move image in selected region idiom that comes from most primitive raster tools.

The best way to do this (i.e. least of all hacky ways) is to do the following:

1. Press r and select a rectangular region.
2. Then, apply C-S-l. This causes the selection to be a floating layer.
3. Move at will. Ensure that your mouse cursor is actually on a part of the image that is in the floating layer, i.e. don't click on the transparent ``no pixels'' part.
4. Click anywhere outside the image to stop moving that layer

I find myself needing this more when I start to adjust scores by scanning them as high quality (600 dpi) grayscale images before manipulating them, often to generate a more compact copy (e.g. from 3 pages to 2).