I started my project at 1/8ths.
I decided to change to 16th triplets, but when I move the notes with the Smart tool, they just do not want to snap to the new grid setting. They still jump to the old grid.
 
I have turned on the grid lines, the global grid is on (smart grid off) and the local grid in the PRV is also on. All 16th triplets.
The lengths also won't snap to the gridlines when I drag the tails.

Are you aware that the snap settings for MIDI can be (but don't have to be) different from the snap settings in the control bar?

No. But I do see there are two grids - the one in the control bar and the one in the PRV. I set BOTH to 16th triplet (although the control bar one then displays 1/4 [3], but if you look in the dropdown, it HAS selected 16th triplet).
 
And any new notes I draw do snap to the changed grid setting, so the grid in the PRV does seem to be as I want it.
 
But it's the old notes that stubbornly jump over the grid lines and snap to where there is no grid line anymore.

Check that in the PRV, under the View menu, you have Grid Resolution > Follow Snap Settings is checked

Yes, I already had tried that. Makes no difference whether I use Follow Snap Settings or tell it to use 16th triplets directly.

Aaah... got it.
In the main console next to the grid button is a toggle saying "To" or "By".
I know what this does so of course I had it set to "To".
 
HOWEVER!
 
In the PRV, the local grid there ALSO has this function, but it is hidden inside the popup menu.
Default was "Snap By". Changed it to "Snap To" and now it works like I want it to.
All perfectly logical.
 
Hoo boy.
I started with Cakewalk 4 for DOS back in the day and I'm still finding things out.
 

@Craig Anderton & Bristol_Jonesey - Many thanks.

As an afterthought, I notice on a fresh - Blank Project - both the switch in the console and the local PRV grid has this set to "Snap By".
 
Isn't this rather the special case?
 
I want to post a Feature Request asking the Bakers to change the startup default to "Snap To" in both cases.
 
Are there any arguments why the current situation is desirable?

Hard to imagine any use at all for "snap by", so yes please post your feature request.