WPF - OnLostMouseCapture with active scrolling.

[timaiv]

• What version of the product are you using?
  v85.3.130

• What architecture x86 or x64?
  Both

• On what operating system?
  Win10

• Are you using WinForms, WPF or OffScreen?
  WPF

• What steps will reproduce the problem?
  1)Draging the scrollbar with left button pressing
  2)move the cursor out of the browser control
  2)press alt+tab, choose other app.
  3)release left button.
  4)move mouse in browser, browser is thinking that mouse is pressed.

• Please provide any additional information below.
  As i said in WPF - Capture/Release mouse to allow scrolling outside bounds of browser control #2871 we have problem with OnLostMouseCapture.
  Default wpf implementation does not raise mouse up event after lost mouse capture.

  Worked fast fix(SubClass):

        private bool isLeftMouseDown;
        protected override void OnMouseDown(MouseButtonEventArgs e)
        {
            isLeftMouseDown = e.LeftButton == MouseButtonState.Pressed;
            base.OnMouseDown(e);
        }

        protected override void OnLostMouseCapture(MouseEventArgs e)
        {
            var modifiers = e.GetModifiers();
            var point = e.GetPosition(this);

            if (isLeftMouseDown)
            {
                GetBrowser().GetHost().SendMouseClickEvent((int)point.X, (int)point.Y, MouseButtonType.Left, true, 1, modifiers);
                isLeftMouseDown = false;
            }

            base.OnLostMouseCapture(e);
        }

[amaitland]

Thank you for the detailed bug report.

Can you please submit a PR with your proposed changes. Thanks.