AvalonDock finding drop target is very slow.

[ucyildirim]

Hi there.

I'm trying to use and test the AvalonDock.

I've DockingManager with LayoutDocumentPaneGroup contains LayoutDocumentPane.

Steps to produce

1- Open more than 40 documents. 2- Make one Float. 3- Drag that floating document over others.

Once you do that, you will see that the floating window will studder because of the lines below. Theese lines taking about 200ms on every mouse move.

https://github.com/xceedsoftware/wpftoolkit/blob/61789cfce1669938d8b38e9c265304d095a0a239/ExtendedWPFToolkitSolution/Src/Xceed.Wpf.AvalonDock/Controls/OverlayWindow.cs#L408-L414

[XceedBoucherS]

Hi, Could you submit a sample where we can see how slow it can be ? Here's one where there is no lag:

`<Window x:Class="_1651.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:xcad="http://schemas.xceed.com/wpf/xaml/avalondock" mc:Ignorable="d" Title="MainWindow" Height="450" Width="800">

`

` public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); }

private void Button_Click( object sender, RoutedEventArgs e )
{
  var myList = new List<Button>();
  for( int i = 0; i < 40; ++i )
  {
    myList.Add( new Button() { Content = "But" + i, Height = 200 } );
  }

  _dockingManager.DocumentsSource = myList;
}

}`