Trim Mode Preview when slipping video turned off

What I'm referring to is when I enter Trim Mode (T), I used to be able to hover over the top of the clip and "click to preview" the beginning and endpoints. In a project, I somehow turned that off? If I hold Shift, I see a full-frame preview but not the in-and-out preview like I'm used to. Where is that toggle?

I don't know that the clip extents were ever shown with just a hover, but they are still showing up for me with a left click.

I'm not aware of any way to turn those off.

Studio 19b1 on Windows 11.

Is this what you mean?
In the Cut page left click on an edit to see this, right click to close.

Trim in the Cut Page.jpg (379.78 KiB) Viewed 300 times

In the Edit page double left click to open, single left click to close. It's different to the Cut page as a right click brings up further options.

Trim in the Editt Page.jpg (321.02 KiB) Viewed 300 times

If you mean Show Preview Marks for 3 point editing, it is in the View dropdown menu. Have a look at page 766 of the 18.6 Reference Manual.

The "DaVinci-Resolve-18-Editors-Guide" might be more helpful than the manual. It's free too.