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        private void timer1_Tick(object sender, EventArgs e)
        {
            if (MouseButtons == MouseButtons.Right)
            {
                while (MouseButtons == null)
                {
                    Application.DoEvents();
                    //Mach etwas
                }
            }
        }                    

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        MouseButtons mouseButtons = MouseButtons.None;
        int i = 0;
        private void timer1_Tick(object sender, EventArgs e)
        {
            if (MouseButtons == MouseButtons.Right)
            {
                this.mouseButtons = MouseButtons;
            }

            if (this.mouseButtons == MouseButtons.Right)
            {
                if (MouseButtons == MouseButtons.None)
                {
                    this.Text = i++.ToString();
                    this.mouseButtons = MouseButtons.None;
                }
            }
        }