Gimp selection modes: I am confused

[Browser_ice]

In my moving to Linux, I got rid of a lot of Windows software. In doing this I used to have Photoshop but now I am forcing myself to use Gimp.

One thing which is confusing me a lot is the selection modes in Gimp.

It seams that even if I do a selection, once I am done, I can see the selection borders being inside another selection and I do not know how to make my selection baked into the image after something I have done.

Ex: doing a perspective manipulation on a selection area (partial image selection). When the perspective is done, that selection is still active. I do not know how to remove that manual selection I did to bake the resulted transformation into the rest of the image. I tried doing a Selection None or All but I still see 2 selection areas: mine and the canvas one. The resulted transformation becomes a floating selection layer.

In photoshop, I selected an area did a transform on it and applied it. It was baked into the rest of the image.

I know I must not work with Gimp in terms of applying work on it like I used to do with Photoshop.

[eightmillion]

After you do the transformation, you should have Floating Selection (Transformation) among your layers. You can right click on it and either select New Layer to make it its own layer or you can select Merge Down to anchor it to the layer that you are working on.

[oedipuss]

Or you can grab a selection tool, and click anywhere outside the selection. The pointer should have an anchor emblem to indicate that clicking means drop or merge down.
The yellow dashed rectangle is the layer boundaries, it hasn't got anything to do with selections. It just shows up because the floating layer is smaller than the others, as it is cropped to contain the selection only. Right click on a layer to see some options on modifying it; for instance Layer to image size scales the layer boundary to the full image. You can hide it completely [menu View/Show layer boundary] but it's useful sometimes.

A little unrelated thing that might help: if you want to move the selected part of an image instead of the selection rectangle itself, hold down ctrl+alt and drag.
At least, it took me a while to figure that out :P
Kind of unfortunate that most of the default compiz shortcuts use ctrl+alt drag, and completely override that :P