Copy & Cut
"Copy" will really work like you expect it. It copies the selected region into the clipboard.
But it won't copy the region if it would lead to an incorrect string.
Cutting out means in this term not cutting out like in other text editors. Here you cut the part out and
throw the rest away. So you will get something like below if you choose "Cut" in the DNA window above.
If the cutted region would result in an incorrect DNA string it won't be cut, but there will appear a message
in the statusbar.