I have a rectangle selection. As long as I stay on the rectangle selection tool I can click in the rectangle to change the size.
If I switch to another tool (e.g. move tool) and then come back to the rectangle selection tool it seems I can no longer edit the size of the selection. What I'd like is to be able to somehow re-activate the selection so that I can resize it to adjust the dimensions.
Is this possible in GIMP or do I have to create a brand new selection?
If - while making the selection - you know that you will want to come back to it later, you can save it using the selection menu and restore the selection using the channels dialogue.
So say you have your image and you want to save a particular selection, you can: