Add TlistItems/PVirtualNodes synchronized

[Snify]

Hello,

I would like to add items to a listview/virtual treeview.
The problem is the following:

My application has Indy server 9 and I want to add a tlistitem/pvirtualnode every time the OnConnect gets fired. Unfortunately the OnConnect gets fired as a thread so if I get 1+ connections at the same time - it will add the items/nodes asychronized and the app causes to crash. I used CriticalSections but it seem not to work... (skips to add items/nodes sometimes)

I heard I should use PostMessage or TThread but I never used it before.

Does anybody have a solution?

Here is my code: (Delphi7 / Indy9)

procedure TForm1.IdTCPServer1Disconnect(AThread: TIdPeerThread);
begin
VirtualStringTree1.DeleteNode(PVirtualNode(Athread .Data)); // For Disconnection(s)
end;

procedure TForm1.IdTCPServer1Connect(AThread: TIdPeerThread);
begin
Athread.Data := TObject(VirtualStringTree1.AddChild(NIL)); // For Connection(s);
end;