MouseHover and MouseLeave Events controlling

Question

I was building a simple form with one simple effect- opacity reduced when mouse is not over the form, and form becomes opaque when mouse is over it. I am currently encounter

Answer 1

The MouseEnter/Leave events are too unreliable to do this. Best thing to do is just use a Timer that checks if the mouse is still inside the window. Drop a Timer on the form and make the code look like this:

public partial class Form1 : Form {
    public Form1() {
        InitializeComponent();
        this.Opacity = 0.99;
        timer1.Interval = 200;
        timer1.Enabled = true;
        timer1.Tick += timer1_Tick;
    }
    protected override void OnLoad(EventArgs e) {
        base.OnLoad(e);
        timer1_Tick(this, e);
    }
    private void timer1_Tick(object sender, EventArgs e) {
        this.Opacity = this.Bounds.Contains(this.PointToClient(Cursor.Position)) ? 0.99 : 0.20;
    }
}

Btw: avoid increasing the Opacity to 1.0, that forces the native window to be recreated and that can have a lot of side-effects. Using 0.99 is best.