Program freezes but the CPU utilization is zero

Question

Sometimes my program freezes. If i click \'Pause program\' it shows me this:

ntdll.RtlUserThreadStart:
773301C4 89442404         mov [esp+$04],eax
773301C8 8         


        

Answer 1

I am making progress here! I have found a similar issue in a program of mine. The freeze appears when I try to load a large text (over 100000) in a custom list box because of this code:

MyListBox.Items.Text:= xxx;


procedure TMyListBox.LBADDSTRING(var M: TMessage);   { This makes the control slow when I work with 100000 lines }
begin
 inherited;
 if Assigned(FOnChange)
 then FOnChange(Self, lbAdded);
end;

The execution point runs through LBADDSTRING for every line (100000 times). So, it seems frozen.

Odd is also the fact, that if I pause the program, Delphi cannot accurately show the execution point for my program (I checked all 5 threads). So, all this is in the end a Delphi debugger flaw.