[RWP] Nudge Selected Item left and its relation to snap to grid

[Indigo]

I was trying to fix a slight gap at the beginning of a midi item today, 
where it the first note came a tiny bit late after 1 measure 1 beat, 
which cause a gap; when looping.
I tried selecting and nudgeing left with comma and period, but these 
seem not to work.
I now realize that the standard Reaper shortcuts NumPad 4  and 6 will 
nudge a selection left or right, and the numPad plus/minus will control 
the nudgeing amount, but can I get snap to grid this way?
Also, can I nudge too much left; so that the first note disappears to 
the left past zero, or will it stop when it reaches zero and not nudge 
farther left?
Do I need to define a time selection beginning at the first note and 
ending at the last note before I begin the nudge to the left?
Thanks,
Indi