Delphi: bug when resizing columns of List View (on DrawItem) - delphi

Question

Enable Autosize of columns and enable OwnerDraw for a List View. Then add a code below from HERE:
procedure TForm1.ListView1DrawItem(Sender: TCustomListView; Item: TListItem;
Rect: TRect; State: TOwnerDrawState);
var
i: Integer;
x1, x2: integer;
r: TRect;
S: string;
const
DT_ALIGN: array[TAlignment] of integer = (DT_LEFT, DT_RIGHT, DT_CENTER);
begin
if SameText(Item.SubItems[1], 'done') then
begin
Sender.Canvas.Font.Color := clWhite;
Sender.Canvas.Brush.Color := clGreen;
end
else
if Odd(Item.Index) then
begin
Sender.Canvas.Font.Color := clBlack;
Sender.Canvas.Brush.Color := $F6F6F6;
end
else
begin
Sender.Canvas.Font.Color := clBlack;
Sender.Canvas.Brush.Color := clWhite;
end;
if odSelected in State then // NEW!
begin // NEW!
Sender.Canvas.Font.Color := clWhite; // NEW!
Sender.Canvas.Brush.Color := clNavy; // NEW!
end; // NEW!
Sender.Canvas.Brush.Style := bsSolid;
Sender.Canvas.FillRect(Rect);
x1 := 0;
x2 := 0;
r := Rect;
Sender.Canvas.Brush.Style := bsClear;
Sender.Canvas.Draw(3, r.Top + (r.Bottom - r.Top - bm.Height) div 2, bm);
for i := 0 to ListView1.Columns.Count - 1 do
begin
inc(x2, ListView1.Columns[i].Width);
r.Left := x1;
r.Right := x2;
if i = 0 then
begin
S := Item.Caption;
r.Left := bm.Width + 6;
end
else
S := Item.SubItems[i - 1];
DrawText(Sender.Canvas.Handle,
S,
length(S),
r,
DT_SINGLELINE or DT_ALIGN[ListView1.Columns[i].Alignment] or
DT_VCENTER or DT_END_ELLIPSIS);
x1 := x2;
end;
if odFocused in State then // NEW!
DrawFocusRect(Sender.Canvas.Handle, Rect); // NEW!
end;
Actively resize the penultimate column if it has autosize. It bill be bugs:
How to prevent these bugs?­­­­­­­­
Thanks!

Answer 1

The bug is in the TListColumn.GetWidthin 'comctrls.pas'. The VCL is retrieving a wrong column width while resizing columns when 'AutoSize' on the columns is set, hence you're drawing item text all over the columns.
I looked at the VCL code for a few minutes and couldn't figure out what's wrong, but setting the value in a getter is suspicious enough.
Anyway, for a workaround, instead of
inc(x2, ListView1.Columns[i].Width);
use this:
inc(x2, ListView_GetColumnWidth(ListView1.Handle, ListView1.Columns[i].Index));