Very occasionally, hit
SPC during regular typing and get an unexpected abbrev expansion. What I usually do in this case is
undo (which reverts the expansion and the inserted space) and then manually
C-q SPC to add the space again.
It would be really useful if, when I hit
undo, only the expansion would get reverted, but the space would stay. Then, hitting
undo a second time could revert the space insertion too. This is what you usually see in editors with auto-correction features (the first undo affects the correction, the second affects the space you typed).
How can I achieve this?