Also, you might wanna make the changes from this commit to see what happens in another "toggle" scenario.

Thank you Corey. I've added new commit to clean up my code. Please review again.

Thank you! I've merged your suggestion.

@kzys sorry if I didn't explain myself fully, that first half of the if was still totally valid, that was just a replacement for the else case... Also, could you maybe move that zero var definition up into the var statement?

Finally I understand your point.

On #sizeToggle of "visual effects test" page (It's very helpful. Thank you), First toggle hide element and second toggle show element again. And second animation looks odd because it's zero -> original.

However, It's problem of show, not toggle. We should swap from/to on show because other effect do this. For example, $(shown).hide('slide', { direction: 'left' }); is slide to left, but $(hidden).show('slide', { direction: 'left' }); is slide from left.

I think I'm sold on the reverse direction for show... All the time... Because of your point about the directions on slide/etc. We really need to document that behavior though...

For right now, can you put the if back in that works for toggle show only? I'd like to at least get this change in to fix this bug for the toggle case... We can further discuss the fate of the rest of show animations for size later...

Like this?

Not quite, you still need the direction detection in the "else" :

if ( o.mode === "toggle" && mode === "show" ) {
    el.from = o.to || zero;
    el.to = o.from || original;
} else {
    el.from = o.from || ( mode === "show" ? zero : original );
    el.to = o.to || ( mode === "hide" ? zero : original );
}

Oh, Sorry. I've fixed (actually just a copy-and-paste...).

This no longer wants to merge cleanly, could you rebase / merge with changes upstream?

Also, make sure to cover the whitespace issues :)

There have been a lot of changes upstream, I'd like to keep this fix, if you want to re-make it on top of a clean master that would be awesome. Please re-open / make a new pull when you get this mergable.

Okay.