TDBAdvGrid + Lookup Fields - Dropdown problem

Could you tell which situation could led to a lookupfield column not displaying the max rows possible when it's combo box drops down ?
The dropdown rows should be:
min(lookupdataset record count; grid.ControlLook.DropDownCount)
, but I'm getting:
min(lookupdataset record count; grid.ControlLook.DropDownCount) - 1 .

MyGrid.ControlLook.DropDownCount = 8.

In this column, just 7 rows:

In this case, same grid, same record, smaller lookupdataset (with only 2 records), showing just 1 row:

Could it be a Dataset, dpi, font size, style, etc. issue ?
Not much trouble when the lookup dataset has 5 or more rows, but f.i. when it has just 2 rows, my dropdown is showing just 1 value.

I took the Lookup demo and tried to replicate it, but no way. Even changed the demo's datasets to FDMemTables as I use them in my program, and nothing weird happened. Copied/Pasted the demo grid into my frame, and then the same weird dropdown with a missing row.

Could you suggest something else I could check ?

Thanks !

I retested this here, with & without frame and on 100% DPI and 150% DPI but I could not reproduce this.
If a problem persists, please try to isolate this and send a sample source project with which we can reproduce the issue.

Must be something at project level, or a used unit that is hooking something. Creating a brand-new empty Form in the same project, the frame produces the error.

Creating another project and using the frame on a new form with the same containers (Panels, PageControl, PolyPage, etc) structure, and same data access objects there's no error.

I could someway solve it changing DBAdvGrid's DefaultRowHeight.
It was 22, and my font was Segoe UI Size 9 (Height -12).
In DBAdvGrid/AdvGrid source code I've seen that the number of drop items shown depends on cell height, so I noticed when I changed it's Font to 8 (-11) I got the 2 lines in the combo drop down. So I increased DefaultRowHeight.

I still can't tell what makes it fail in the existing project and work well in a new one with the same dpi awareness, method, same VCL Style, etc.

Anyway, there's still an open question: Why did it reduce the number of combo items shown instead of having calculated a proper height to fit all the items that should be shown?