BUG: Pressing ESC Twice in Combo Box Resets ListIndex Property

MORE INFORMATION

The ListIndex property of a list box or combo box specifies the index number of the selected item in a combo box or list box control. The index number should be a non-zero value if an item is selected. However, in this case, it returns a zero value for the index number even though an item is selected.

Steps to Reproduce Behavior

The following example echoes the method being called and the value of the combo box ListIndex property each time either the Valid or KeyPress events of the combo box execute.

1. Run the following code from a program (.PRG) file:

         PUBLIC oform1
         oform1=CREATEOBJECT("form1")
         oform1.SHOW
   
         DEFINE CLASS form1 AS FORM
            AUTOCENTER = .T.
            NAME = "Form1"
            DIMENSION aarray[1]
   
            ADD OBJECT combo1 AS COMBOBOX WITH ;
               ROWSOURCETYPE = 5, ;
               ROWSOURCE = "thisform.aArray", ;
               HEIGHT = 24, ;
               LEFT = 144, ;
               TOP = 36, ;
               WIDTH = 100, ;
               NAME = "Combo1"
   
            ADD OBJECT edit1 AS EDITBOX WITH ;
               HEIGHT = 109, ;
               LEFT = 12, ;
               TOP = 96, ;
               WIDTH = 348, ;
               NAME = "Edit1"
   
            PROCEDURE LOAD
               DIME THIS.aarray[10]
               FOR lni = 1 TO ALEN[this.aArray]
                  THIS.aarray[lni] = 'Number '+ALLTR(STR(lni))
               ENDF
            ENDPROC
   
            PROCEDURE combo1.VALID
               THISFORM.edit1.VALUE = PROGRAM()+' '+STR(THIS.LISTINDEX)+ ;
                  CHR(13)+ THISFORM.edit1.VALUE
            ENDPROC
   
            PROCEDURE combo1.KEYPRESS
               LPARAMETERS nKeyCode, nShiftAltCtrl
               THISFORM.edit1.VALUE = PROGRAM()+' '+STR(THIS.LISTINDEX)+ ;
                  CHR(13)+ THISFORM.edit1.VALUE
            ENDPROC
   
         ENDDEFINE

2. Click the down arrow of the combo box to open the combo box. Using the mouse, select "Number 2" from the combo box. This closes the combo box.
3. Next, click the down arrow of the combo box to open the combo box again. Press the ESC key twice. The first click closes the drop-down combo box. The second ESC resets the value the ListIndex to zero (0).