Comboboxes are a pain anyway. I try to use for as little items as possible an pop up a pick form if it goes larger.
Anyway I found a combobox that as 4 times as much elements then the visible area covers. Scrollbar is visible.
I open the list by clicking the button like area on the combobox. I move the mouse in the list area, and the area scrolls up and down without selecting something (as expected), if I press [Cursor up] or [cursor down] the marker defining the selected item moves up and down. Clicking an item selects the item.

I have akwardnes with combos in grids, but you use the combo outside a grid, right?

Can you give more information about the combo? RowSourceTyp, how do you create the data, the like?

There is some code in Keypress dealing with [Backspace] on empty combo (do not focus previous element) and [CTRL+0] (do not allow .NULL. entry), but nothing more

LPARAMETERS;
 tnKeyCode,;
 tnShiftAltCtrl

DO CASE
 CASE THIS.SELSTART=0 AND tnKeyCode=127
  NODEFAULT
 CASE THIS.glAllow_Null_Input
 CASE tnShiftAltCtrl=2 AND tnKeyCode=48
  NODEFAULT
ENDCASE

>Error:
>If combobox (style=2 dropdownlist) had more elements and scrollable area, the mouse element selection did not work properly. Same with up and down arrow keys. It was 4 years ago, move from vfp6 to 9, hundreds computers with win 7 to 10.
>From internet I put in MouseUp event of my base combo class:
>LPARAMETERS nButton, nShift, nXCoord, nYCoord
>inkey(.1)
>
>
>>After upgrade from VFP6 to 9 I have problems with comboboxes with more elements.
>>Somebody (thanks again) help me with:
>>inkey(.1)
>>in MouseUp() event
>
>I'm not really sure what you are talking about. Can you give a larger code snippet and a more precise description of the error.
>- what is the goal of the code
>- what is the problem now
>
>Anyway, the use of INKEY() is depreciated in OOP from the start. There is the KeyPress event, and using INKEY will mess it up.