Copy and paste does not work with free-selection tool in GIMP

Question

I have started using GIMP 2.10.8 on Linux and want to cut an arbitrary piece of an image, copy, and paste it. All image editing programs support this except GIMP - why?

Step-by-step reproduction of behaviour: Use the "free select tool" from the toolbox, select an area of the image (e.g. free form or polygon), press Ctrl + C to copy selection, then Ctrl+V to paste selection. Nothing happens. Also, drag & drop does not work, i.e. the selected region cannot be moved.

UPDATE: When using the "move" tool to translate the selection, something strange happens. It seems that copy & paste creates a duplicate of the entire image and layers it behind the current image. Moving the small selection then translates the entire duplicate layer behind the original image and the selected region behaves sort of like a "window" through which the layer behind is visible. Or differently put: The free-selection tool seems to select the complement of the actual selection. In order to understand how abnormal this behaviour is: Imagine that you select a word in this sentence and do Ctrl + C and Ctrl + V. You would not expect the entire text on this site (minus the selected word) to be copied. But this is precisely what GIMP does.

Answer 1

I found the solution, which is as simple as it is stupid: The "free selection" tool requires confirmation of the selection by pressing Enter. Without confirmation, GIMP will select anything that it deems appropriate at the moment, just not your selection (IMHO a bug/inconsistency, as e.g. the square selection tool works without pressing Enter).

I want to point out, however, that both Xenoid's and - especially - Anaksunaman's answer is extremely instructive as they explain the different settings that can be active while the selection is made.

Answer 2

Please add a screen shot of your Gimp UI, including the Tool options for the selection tool, and the Layers list.

IMHO what happens is that your selection tool is not in Replace mode (leftmost) but in Subtract mode:

In addition before doing this at some point you also did Select>All so the end result is that:

1. What you selected is really the opposite of your selection because what you enclosed with the selection tool is subtracted from the rest.
2. When you copy+paste, you create a new layer with a "hole" where your selection was.
3. When you try to move it, the Move tool sticks to the topmost non-opaque layer, and since you are clicking on the hole, it sticks to the bottom layer instead and moves it.

There are several ways to check your selection:

1. The quick mask: when it is active, the selected part is "clear" and the non -selected par is overlaid with a semi-transparent color (red, by default)
2. The Selection Editor that shows in white what is selected and in black what is not.
3. To distinguish a "hole selection" from a plain selection, you can check if the "marching ants" are also marching along the canvas border (instead of just around your selection).

Answer 3

I have started using GIMP 2.10.8 on Linux and want to cut an arbitrary piece of an image, copy, and paste it. All image editing programs support this except GIMP - why?

GIMP supports this.

Step-by-step reproduction of behaviour: Use the "free select tool" from the toolbox, select an area of the image (e.g. free form or polygon), press Ctrl + C to copy selection, then Ctrl + V to paste selection. Nothing happens.

As pointed out in Xenoid's excellent answer, you should generally have the Replace mode activated in the Free Select tool for simple "cut/paste" operations:

ex. Free Select Tool - Replace mode (Option 1)

Also, typically nothing else should be selected before starting your select/copy process (running Select → Select None beforehand may be wise) and you should make certain the layer you want to copy from is selected in the Layers pane (ex. by clicking on it).

You should also double-check the Layers pane after pressing Ctrl + V. You should see a new "floating" layer appear:

ex. Pasted Selection (created after Ctrl + V)

This layer should be selected automatically. You should then be able to Right-Click the Layers pane and choose the To New Layer option to create a new layer containing only the portion of the original image you selected with the Free Select tool:

ex. GIMP Layer Options

This new layer should (again) be selected automatically and you can then use e.g. the Move tool to interact with it:

ex. Pasted Layer

Also, drag & drop does not work, i.e. the selected region cannot be moved.

You may be encountering an issue with the mode of the Move tool. It can be toggled to move layers or selections (and technically paths as well):

ex. Move Layer (Option 1)

ex. Move Selection (Option 2)

Beyond that, as again mentioned in Xenoid's answer, make certain there is no selection around the border of the image in addition to your selection in the center. Also, be aware that a "static box" like the one below can require that the Move tool be set to move layers (as already noted) to affect its placement:

ex. Moving A Pasted Layer