@JanVanBekkum When you click with the mouse, left click & hold, then right click will give you different lasso options.

I have a script that selects all in the chosen track. Copy & paste this into a notepad file with .cs as it's extension, give t a name, then that script will appear in Vegas - Tools - Scripting.

using System;
using System.Collections.Generic;
using System.Collections;
using System.IO;
using System.Text;
using System.Windows.Forms;
using System.Globalization;
using System.Drawing;
using System.Runtime;
using System.Xml;
using ScriptPortal.Vegas;

namespace Test_Script
{
    public class Class1
    {
        public Vegas myVegas;

        public void Main(Vegas vegas)
        {
            myVegas = vegas;

            foreach (Track myTrack in myVegas.Project.Tracks)
            {
               foreach (TrackEvent evnt in myTrack.Events)
                {
                    evnt.Selected = myTrack.Selected;
                 }
            }
        }
    }
}

public class EntryPoint
{
    public void FromVegas(Vegas vegas)
    {
        Test_Script.Class1 test = new Test_Script.Class1();
        test.Main(vegas);
    }
}

PS, I have that script pinned to the top of the UI for easier access.