The C above is not correct. Please ignore it.

Suggestion 1:
In some editors (e.g. UltraEdit, Notepad3), an auto-indent is added in 2 steps (the newline character, then the indent). Thus it can be undone in 2 steps.
So when I add a new line but don’t want to indent it, I just press Enter key and then Ctrl+Z.
This is really convenient, since an indent is often not just a single character.

Suggestion 2:
Select some indented lines.
Use “Select Ending of Lines” command.
Press Enter key.
How about indenting all the new lines (but in the manner mentioned in Suggestion 1)?

“Indent Column” in “All Commands” menu needs an “s”.