Move the processing into a separate thread. Your problem appears to be that Windows thinks the app has stopped responding because it's not processing it's message loop.
Calling Application.ProcessMessages is the wrong solution, because it does a lot more than you might think. You can end up with problems with reentrancy, or things happening that you don't expect.
Make sure that the thread calls CoInitialize before it creates the COM object, and calls CoUnitialize when it's done. You can find examples of using COM in a thread here; the article refers to ADO, but demonstrates the use of CoInitialize/CoUninitialize.
EDIT: After the comments, I'm adding an example of receiving a custom message in a Delphi app. The thread will need access to the UM_IDDELETED constant; you can do this by (preferably) adding it to a separate unit and using that unit in both your main form's unit and the thread's unit, or simply by defining it in both units.
// uCustomMsg.pas
const
UM_IDDELETED = WM_APP + 100;
// Form's unit
interface
uses ..., uCustomMsg;
type
TForm1=class(TForm)
// ...
private
procedure UMIDDeleted(var Msg: TMessage); message UM_IDDELETED;
//...
end;
implementation
procedure TForm1.UMIDDeleted(var Msg: TMessage);
var
DeletedID: Integer;
begin
DeletedID := Msg.WParam;
// Remove this item from the tree
end;
// Thread unit
implementation
uses
uCustomMsg;
// IDListIdx is an integer index into the list or array
// of IDs you're deleting.
//
// TheFormHandle is the main form's handle you passed in
// to the thread's constructor, along with the IDList
// array or list.
procedure TYourThread.Execute;
var
IDToDelete: Integer; // Your ID to delete
begin
while not Terminated and (IDListIdx < IdList.Count) do
begin
IDToDelete := IDList[IDListIdx];
// ... Do whatever to delete ID
PostMessage(TheFormHandle, UM_IDDELETED, IDToDelete, 0);
end;
end;
