EasyMap VCL
TEasyMap.OnChangingCurrentTool
property OnChangingCurrentTool: TChangingCurrentToolEvent;
Description
Event occurs when current tool is about to be changed.

procedure TForm1.EasyMap1ChangingCurrentTool(Sender: TEasyMap;
  MapTool: TMapTool; var AllowSetTool: Boolean);
begin
 if MapTool = mtZoomIn then AllowSetTool := False; //никогда не будет доступен инструмент mtZoomIn
end;