Fixed column support drag?

[chinawsb]

I place a fixed column in left(for example:row no),but user can drag a no fixed column before it .Why allow this operation?
In my mind,fixed column should not alway before any no fixed column.

[chinawsb]

I add some code fix this in unit VirtualTrees.Header:

`
procedure TVTHeader.DragTo(P : TPoint);

//Moves the drag image to a new position, which is determined from the passed point P and the previous
//mouse position.

var
I, NewTarget : Integer;
//optimized drag image move support
ClientP : TPoint;
Left, Right : TDimension;
NeedRepaint : Boolean; //True if the screen needs an update (changed drop target or drop side)

begin
//Determine new drop target and which side of it is prefered.
ClientP := Tree.ScreenToClient(P);
//Make coordinates relative to (0, 0) of the non-client area.
Inc(ClientP.Y, FHeight);
NewTarget := FColumns.ColumnFromPosition(ClientP);
NeedRepaint := (NewTarget <> InvalidColumn) and (NewTarget <> FColumns.DropTarget);
if NewTarget >= 0 then
begin
FColumns.GetColumnBounds(NewTarget, Left, Right);

//swish patch:Fixed column not allow drag to
if coFixed in FColumns[NewTarget].Options then
begin
  if FColumns.IsLastVisibleLeadingFixed(NewTarget) then
  begin
    if (ClientP.X < Divide((Left + Right), 2)) = FColumns.DropBefore then
      Exit;
  end
  else
    Exit;
end;
//swish patch:end

if (ClientP.X < Divide((Left + Right), 2)) <> FColumns.DropBefore then
begin
  NeedRepaint := True;
  FColumns.DropBefore := not FColumns.DropBefore;
end;

end;

`

[chinawsb]

procedure TVirtualTreeColumn.SetOptions(Value : TVTColumnOptions);

add
if coFixed in Value then Value := Value - [coDraggable];
before
FOptions := Value;

[joachimmarder]

Please respect our guidelines on the project homepage for submitting bugs. Please include your version of Virtual TreeView and Delphi, and attach a sample compiling project as ZIP to your report that allows to replicate the problem. If only small changes are required, a description is sufficient how a demo projects needs to be changed in order to replicate the bug. If you already have a solution, please supply a patch file or a pull request.