internal void OnFloatWindowEnterMove(FloatWindow floatWindow)
{
Debug.Assert(floatWindow != null);
if (!IsDragging)
BeginDrag(floatWindow, null, null);
}
internal void OnFloatWindowMove(FloatWindow floatWindow)
{
if (IsDraggingFloatWindow)
{
Debug.Assert(_floatWindow == floatWindow);
Drag();
}
}
internal void OnFloatWindowExitMove(FloatWindow floatWindow)
{
if (IsDraggingFloatWindow)
{
Debug.Assert(_floatWindow == floatWindow);
EndDrag(!Keyboard.IsKeyDown(Key.Escape));
}
}
/// <summary>
/// Tries to move the dragged items from the <see cref="FloatWindow"/> into a
/// <see cref="DockTabPanel"/>.
/// </summary>
private void DragFloatWindowIntoDockTabPanel()
{
Debug.Assert(_targetDockTabPane == null);
Debug.Assert(_floatWindow != null);
var dockTabPane = GetTargetPane() as DockTabPane;
if (dockTabPane == null)
{
return; // No DockTabPane (view).
}
var dockTabPaneVM = dockTabPane.GetViewModel();
if (dockTabPaneVM == null)
{
return; // No IDockTabPane (view-model).
}
if (GetDockTabItemAtMouse(dockTabPane) == null)
{
return; // No DockTabItem hit.
}
if (!CanDock(dockTabPaneVM, DockPosition.Inside))
{
return; // Docking not allowed.
}
// Remove currently dragged FloatWindow.
var floatWindowVM = _floatWindow.GetViewModel();
foreach (var item in _draggedItems)
{
DockHelper.Remove(floatWindowVM, item);
}
_floatWindow = null;
Win32.ReleaseCapture(); // Exit Win32 move window loop.
// Add items into target DockTabPane.
_targetDockTabPane = dockTabPane;
foreach (var item in _draggedItems)
{
item.DockState = dockTabPaneVM.DockState;
dockTabPaneVM.Items.Add(item);
}
// Make sure the current item is selected in DockTabPane.
_dockStrategy.Activate(_activeItem);
// When the Win32 move window loop exits, the DockControl receives a LostMouseCapture
// event. --> Defer dragging of the DockTabItems.
_dockControl.Dispatcher.BeginInvoke(new Action(() =>
{
if (!_dockControl.IsMouseCaptured)
{
if (!_dockControl.CaptureMouse())
{
// Failed to capture the mouse.
EndDrag(false);
return;
}
_dockControl.LostMouseCapture += OnLostMouseCapture;
_dockControl.MouseMove += OnMouseMove;
_dockControl.MouseLeftButtonUp += OnMouseLeftButtonUp;
_dockControl.PreviewKeyDown += OnPreviewKeyDown;
_targetDockTabPane.PreviewKeyDown += OnPreviewKeyDown;
DragDockTabItems();
}
}));
HideBorderDockIndicators();
HidePaneIndicators();
_dockControl.UpdateFloatWindows();
_layoutChanged = true;
}
/// <summary>
/// Limits the extent of the <see cref="FloatWindow"/> to a reasonable size.
/// </summary>
/// <param name="floatWindow">The <see cref="FloatWindow"/>.</param>
/// <param name="fallbackSize">The fallback size. Can be (NaN, NaN).</param>
private static void LimitFloatWindowSize(FloatWindow floatWindow, Size fallbackSize)
{
Debug.Assert(floatWindow != null);
Debug.Assert(Numeric.IsNaN(fallbackSize.Width) || fallbackSize.Width > 0);
Debug.Assert(Numeric.IsNaN(fallbackSize.Height) || fallbackSize.Height > 0);
double maxWidth = SystemParameters.MaximizedPrimaryScreenWidth;
double maxHeight = SystemParameters.MaximizedPrimaryScreenHeight;
Size size = floatWindow.RenderSize;
if (size.Width > maxWidth)
floatWindow.Width = Numeric.IsNaN(fallbackSize.Width) ? maxWidth : fallbackSize.Width;
if (size.Height > maxHeight)
floatWindow.Height = Numeric.IsNaN(fallbackSize.Height) ? maxHeight : fallbackSize.Height;
}
/// <summary>
/// Starts a drag operation.
/// </summary>
/// <param name="floatWindow">The <see cref="FloatWindow"/> to be dragged.</param>
/// <param name="dockTabPane">The <see cref="DockTabPane"/> to be dragged.</param>
/// <param name="dockTabItem">The <see cref="DockTabItem"/> to be dragged.</param>
/// <returns>
/// <see langword="true" /> if the drag operation has been started; otherwise,
/// <see langword="false" /> if the drag operation could not be started (e.g. because the
/// mouse could not be captured).
/// </returns>
private bool BeginDrag(FloatWindow floatWindow, DockTabPane dockTabPane, DockTabItem dockTabItem)
{
_dockStrategy = _dockControl.GetViewModel()?.DockStrategy;
if (_dockStrategy == null || _dockStrategy.DockControl.IsLocked)
{
Reset();
return(false);
}
FrameworkElement element = null;
IDockTabPane draggedPane = null;
IDockTabItem draggedItem = null;
if (floatWindow != null)
{
// User is dragging a FloatWindow.
// (Note: Dragging of FloatWindows with nested layouts is not supported.)
draggedPane = floatWindow.GetViewModel()?.RootPane as IDockTabPane;
element = floatWindow;
_floatWindow = floatWindow;
_initialSize = floatWindow.RenderSize;
// Start dragging immediately.
_dragDeltaExceeded = true;
}
else if (dockTabItem != null)
{
// User is dragging a DockTabItem in a DockTabPanel.
draggedItem = dockTabItem.GetViewModel();
element = dockTabItem;
_targetDockTabPane = dockTabPane;
_initialSize = dockTabPane.RenderSize;
// Start dragging when threshold is exceeded.
_initialMousePosition = WindowsHelper.GetMousePosition(_dockControl);
_dragDeltaExceeded = false;
}
else if (dockTabPane != null)
{
// User is dragging a DockTabPane.
draggedPane = dockTabPane.GetViewModel();
element = dockTabPane;
_initialSize = dockTabPane.RenderSize;
_initialMousePosition = WindowsHelper.GetMousePosition(_dockControl);
// Start dragging when threshold is exceeded.
_initialMousePosition = WindowsHelper.GetMousePosition(_dockControl);
_dragDeltaExceeded = false;
}
if (draggedPane == null && draggedItem == null)
{
Reset();
return(false);
}
// When the user is dragging the FloatWindow, the mouse is captured by Win32 move window
// loop. When dragging a DockTabPane or DockTabItem, the mouse needs to be
// captured to receive mouse events.
if (_floatWindow == null)
{
if (!_dockControl.CaptureMouse())
{
// Failed to capture the mouse.
Reset();
return(false);
}
_dockControl.LostMouseCapture += OnLostMouseCapture;
_dockControl.MouseLeftButtonUp += OnMouseLeftButtonUp;
_dockControl.MouseMove += OnMouseMove;
_dockControl.PreviewKeyDown += OnPreviewKeyDown;
if (_targetDockTabPane != null)
{
_targetDockTabPane.PreviewKeyDown += OnPreviewKeyDown;
}
}
_dockStrategy.Begin();
if (draggedPane != null)
{
_dockStrategy.Activate(draggedPane);
_activeItem = draggedPane.SelectedItem;
foreach (var item in draggedPane.Items)
{
if (item.DockState == draggedPane.DockState)
{
_draggedItems.Add(item);
}
}
}
else
{
Debug.Assert(draggedItem != null);
_dockStrategy.Activate(draggedItem);
_activeItem = draggedItem;
_draggedItems.Add(draggedItem);
}
Debug.Assert(_draggedItems.Count > 0);
// Determine whether dragged items may end in a FloatWindow.
_canFloat = CanFloat();
// Store the mouse offset relative to the dragged element.
_mouseOffset = (Vector)WindowsHelper.GetMousePosition(element);
// Remember information needed for a rollback.
ReplaceItemsWithProxies(draggedPane ?? _targetDockTabPane.GetViewModel());
_originalDockState = _draggedItems[0].DockState;
BackupFloatWindowPosition();
// Override mouse cursors. (Mouse cursor should not change to caret over text editor.)
Mouse.OverrideCursor = Cursors.Arrow;
return(true);
}
private void DragDockTabItemsIntoFloatWindow()
{
Debug.Assert(_floatWindow == null);
if (_targetDockTabPane != null)
{
ClearTranslateTransform();
_targetDockTabPane.PreviewKeyDown -= OnPreviewKeyDown;
_targetDockTabPane = null;
}
_dockControl.LostMouseCapture -= OnLostMouseCapture;
_dockControl.MouseLeftButtonUp -= OnMouseLeftButtonUp;
_dockControl.MouseMove -= OnMouseMove;
_dockControl.PreviewKeyDown -= OnPreviewKeyDown;
_dockControl.ReleaseMouseCapture();
// Remove the dragged items from their current location.
foreach (var item in _draggedItems)
{
DockHelper.Remove(_dockStrategy.DockControl.RootPane, item);
foreach (var floatWindow in _dockStrategy.DockControl.FloatWindows)
{
DockHelper.Remove(floatWindow, item);
}
DockHelper.Remove(_dockStrategy.DockControl.AutoHideLeft, item);
DockHelper.Remove(_dockStrategy.DockControl.AutoHideRight, item);
DockHelper.Remove(_dockStrategy.DockControl.AutoHideTop, item);
DockHelper.Remove(_dockStrategy.DockControl.AutoHideBottom, item);
}
// Move items into a new FloatWindow.
foreach (var item in _draggedItems)
{
item.DockState = DockState.Float;
}
var newPaneVM = _dockStrategy.CreateDockTabPane(_draggedItems[0], DockState.Float);
for (int i = 1; i < _draggedItems.Count; i++)
{
newPaneVM.Items.Add(_draggedItems[i]);
}
var floatWindowVM = _dockStrategy.CreateFloatWindow();
floatWindowVM.RootPane = newPaneVM;
_dockStrategy.DockControl.FloatWindows.Add(floatWindowVM);
_dockStrategy.Activate(_activeItem);
_dockStrategy.Cleanup();
// Get the newly created FloatWindow (view) from the DockControl.
_floatWindow = GetFloatWindow(floatWindowVM);
Debug.Assert(_floatWindow != null);
LimitFloatWindowSize(_floatWindow, _initialSize);
// Limit mouse offset to FloatWindow size.
double actualWidth = _floatWindow.ActualWidth;
if (actualWidth > 0)
{
_mouseOffset.X = Math.Min(_mouseOffset.X, actualWidth / 2);
}
Point position = GetFloatWindowPosition();
_floatWindow.Left = position.X;
_floatWindow.Top = position.Y;
// Wait until FloatWindow is loaded, initiate the Win32 move window loop.
_floatWindow.Dispatcher.BeginInvoke(new Action(() =>
{
if (_floatWindow != null)
{
LimitFloatWindowSize(_floatWindow, _initialSize);
// Limit mouse offset to FloatWindow size.
_mouseOffset.X = Math.Min(_mouseOffset.X, _floatWindow.ActualWidth / 2);
_mouseOffset.Y = Math.Max(_mouseOffset.Y, 8);
Point pos = GetFloatWindowPosition();
_floatWindow.Left = pos.X;
_floatWindow.Top = pos.Y;
if (Mouse.LeftButton == MouseButtonState.Pressed)
{
_floatWindow.DragMove();
}
else
{
EndDrag(true);
}
}
}), DispatcherPriority.Loaded); // Important: Action needs to be invoked before input.
}
internal void UpdateFloatWindows()
{
if (DockStrategy == null)
return;
var owner = Window.GetWindow(this);
// Close obsolete FloatWindows.
for (int i = _floatWindows.Count - 1; i >= 0; i--)
{
var floatWindow = _floatWindows[i];
var floatWindowVM = floatWindow.GetViewModel();
if (floatWindowVM == null
|| !DockStrategy.DockControl.FloatWindows.Contains(floatWindowVM)
|| !DockStrategy.IsVisible(floatWindowVM))
{
// ----- Close FloatWindow.
floatWindow.Close();
_floatWindows.RemoveAt(i);
}
}
// Open new FloatWindows.
for (int i = 0; i < DockStrategy.DockControl.FloatWindows.Count; i++)
{
var floatWindowVM = DockStrategy.DockControl.FloatWindows[i];
if (DockStrategy.IsVisible(floatWindowVM) && GetView(floatWindowVM) == null)
{
// ----- Open FloatWindow.
// Make sure that the floating window stays on the screen.
// At least 30 pixels must be visible.
const double safety = 30;
double screenLeft = SystemParameters.VirtualScreenLeft;
double screenTop = SystemParameters.VirtualScreenTop;
double screenRight = screenLeft + SystemParameters.VirtualScreenWidth;
double screenBottom = screenTop + SystemParameters.VirtualScreenHeight;
floatWindowVM.Left = Math.Min(Math.Max(floatWindowVM.Left, screenLeft), screenRight - safety);
floatWindowVM.Top = Math.Min(Math.Max(floatWindowVM.Top, screenTop), screenBottom - safety);
var floatWindow = new FloatWindow(this)
{
DataContext = floatWindowVM,
Owner = owner,
};
bool autoWidth = Numeric.IsNaN(floatWindowVM.Width);
bool autoHeight = Numeric.IsNaN(floatWindowVM.Height);
if (autoWidth && autoHeight)
floatWindow.SizeToContent = SizeToContent.WidthAndHeight;
else if (autoWidth)
floatWindow.SizeToContent = SizeToContent.Width;
else if (autoHeight)
floatWindow.SizeToContent = SizeToContent.Height;
else
floatWindow.SizeToContent = SizeToContent.Manual;
floatWindow.SetBinding(ContentProperty, new Binding(nameof(IFloatWindow.RootPane)));
floatWindow.SetBinding(WidthProperty, new Binding(nameof(IFloatWindow.Width)) { Mode = BindingMode.TwoWay });
floatWindow.SetBinding(HeightProperty, new Binding(nameof(IFloatWindow.Height)) { Mode = BindingMode.TwoWay });
floatWindow.SetBinding(Window.LeftProperty, new Binding(nameof(IFloatWindow.Left)) { Mode = BindingMode.TwoWay });
floatWindow.SetBinding(Window.TopProperty, new Binding(nameof(IFloatWindow.Top)) { Mode = BindingMode.TwoWay });
floatWindow.Show();
// Bind WindowState after showing the window. Otherwise, it could be maximized
// on the wrong screen.
floatWindow.SetBinding(Window.WindowStateProperty, new Binding(nameof(IFloatWindow.WindowState)) { Mode = BindingMode.TwoWay });
_floatWindows.Add(floatWindow);
}
}
}
//--------------------------------------------------------------
/// <summary>
/// Resets all fields.
/// </summary>
private void Reset()
{
Debug.Assert(Mouse.Captured == null);
Debug.Assert(_borderDockIndicators == null);
Debug.Assert(_paneDockIndicators == null);
Debug.Assert(
_dockStrategy == null || !_dockStrategy.DockControl.GetDockElements().OfType<DockTabItemProxy>().Any(),
"All item proxies should have been removed.");
_dockStrategy = null;
_draggedItems.Clear();
_activeItem = null;
_floatWindow = null;
_targetDockTabPane = null;
_layoutChanged = false;
_initialMousePosition = new Point(double.NaN, double.NaN);
_dragDeltaExceeded = false;
_mouseOffset = new Vector(double.NaN, double.NaN);
_initialSize = new Size(double.NaN, double.NaN);
_canFloat = true;
_originalDockState = DockState.Hide;
_originalFloatWindow = null;
_originalFloatLeft = 0;
_originalFloatTop = 0;
}
/// <summary>
/// Tries to move the dragged items from the <see cref="FloatWindow"/> into a
/// <see cref="DockTabPanel"/>.
/// </summary>
private void DragFloatWindowIntoDockTabPanel()
{
Debug.Assert(_targetDockTabPane == null);
Debug.Assert(_floatWindow != null);
var dockTabPane = GetTargetPane() as DockTabPane;
if (dockTabPane == null)
return; // No DockTabPane (view).
var dockTabPaneVM = dockTabPane.GetViewModel();
if (dockTabPaneVM == null)
return; // No IDockTabPane (view-model).
if (GetDockTabItemAtMouse(dockTabPane) == null)
return; // No DockTabItem hit.
if (!CanDock(dockTabPaneVM, DockPosition.Inside))
return; // Docking not allowed.
// Remove currently dragged FloatWindow.
var floatWindowVM = _floatWindow.GetViewModel();
foreach (var item in _draggedItems)
DockHelper.Remove(floatWindowVM, item);
_floatWindow = null;
Win32.ReleaseCapture(); // Exit Win32 move window loop.
// Add items into target DockTabPane.
_targetDockTabPane = dockTabPane;
foreach (var item in _draggedItems)
{
item.DockState = dockTabPaneVM.DockState;
dockTabPaneVM.Items.Add(item);
}
// Make sure the current item is selected in DockTabPane.
_dockStrategy.Activate(_activeItem);
// When the Win32 move window loop exits, the DockControl receives a LostMouseCapture
// event. --> Defer dragging of the DockTabItems.
_dockControl.Dispatcher.BeginInvoke(new Action(() =>
{
if (!_dockControl.IsMouseCaptured)
{
if (!_dockControl.CaptureMouse())
{
// Failed to capture the mouse.
EndDrag(false);
return;
}
_dockControl.LostMouseCapture += OnLostMouseCapture;
_dockControl.MouseMove += OnMouseMove;
_dockControl.MouseLeftButtonUp += OnMouseLeftButtonUp;
_dockControl.PreviewKeyDown += OnPreviewKeyDown;
_targetDockTabPane.PreviewKeyDown += OnPreviewKeyDown;
DragDockTabItems();
}
}));
HideBorderDockIndicators();
HidePaneIndicators();
_dockControl.UpdateFloatWindows();
_layoutChanged = true;
}
private void DragDockTabItemsIntoFloatWindow()
{
Debug.Assert(_floatWindow == null);
if (_targetDockTabPane != null)
{
ClearTranslateTransform();
_targetDockTabPane.PreviewKeyDown -= OnPreviewKeyDown;
_targetDockTabPane = null;
}
_dockControl.LostMouseCapture -= OnLostMouseCapture;
_dockControl.MouseLeftButtonUp -= OnMouseLeftButtonUp;
_dockControl.MouseMove -= OnMouseMove;
_dockControl.PreviewKeyDown -= OnPreviewKeyDown;
_dockControl.ReleaseMouseCapture();
// Remove the dragged items from their current location.
foreach (var item in _draggedItems)
{
DockHelper.Remove(_dockStrategy.DockControl.RootPane, item);
foreach (var floatWindow in _dockStrategy.DockControl.FloatWindows)
DockHelper.Remove(floatWindow, item);
DockHelper.Remove(_dockStrategy.DockControl.AutoHideLeft, item);
DockHelper.Remove(_dockStrategy.DockControl.AutoHideRight, item);
DockHelper.Remove(_dockStrategy.DockControl.AutoHideTop, item);
DockHelper.Remove(_dockStrategy.DockControl.AutoHideBottom, item);
}
// Move items into a new FloatWindow.
foreach (var item in _draggedItems)
item.DockState = DockState.Float;
var newPaneVM = _dockStrategy.CreateDockTabPane(_draggedItems[0], DockState.Float);
for (int i = 1; i < _draggedItems.Count; i++)
newPaneVM.Items.Add(_draggedItems[i]);
var floatWindowVM = _dockStrategy.CreateFloatWindow();
floatWindowVM.RootPane = newPaneVM;
_dockStrategy.DockControl.FloatWindows.Add(floatWindowVM);
_dockStrategy.Activate(_activeItem);
_dockStrategy.Cleanup();
// Get the newly created FloatWindow (view) from the DockControl.
_floatWindow = GetFloatWindow(floatWindowVM);
Debug.Assert(_floatWindow != null);
LimitFloatWindowSize(_floatWindow, _initialSize);
// Limit mouse offset to FloatWindow size.
double actualWidth = _floatWindow.ActualWidth;
if (actualWidth > 0)
_mouseOffset.X = Math.Min(_mouseOffset.X, actualWidth / 2);
Point position = GetFloatWindowPosition();
_floatWindow.Left = position.X;
_floatWindow.Top = position.Y;
// Wait until FloatWindow is loaded, initiate the Win32 move window loop.
_floatWindow.Dispatcher.BeginInvoke(new Action(() =>
{
if (_floatWindow != null)
{
LimitFloatWindowSize(_floatWindow, _initialSize);
// Limit mouse offset to FloatWindow size.
_mouseOffset.X = Math.Min(_mouseOffset.X, _floatWindow.ActualWidth / 2);
_mouseOffset.Y = Math.Max(_mouseOffset.Y, 8);
Point pos = GetFloatWindowPosition();
_floatWindow.Left = pos.X;
_floatWindow.Top = pos.Y;
if (Mouse.LeftButton == MouseButtonState.Pressed)
_floatWindow.DragMove();
else
EndDrag(true);
}
}), DispatcherPriority.Loaded); // Important: Action needs to be invoked before input.
}
/// <summary>
/// Starts a drag operation.
/// </summary>
/// <param name="floatWindow">The <see cref="FloatWindow"/> to be dragged.</param>
/// <param name="dockTabPane">The <see cref="DockTabPane"/> to be dragged.</param>
/// <param name="dockTabItem">The <see cref="DockTabItem"/> to be dragged.</param>
/// <returns>
/// <see langword="true" /> if the drag operation has been started; otherwise,
/// <see langword="false" /> if the drag operation could not be started (e.g. because the
/// mouse could not be captured).
/// </returns>
private bool BeginDrag(FloatWindow floatWindow, DockTabPane dockTabPane, DockTabItem dockTabItem)
{
_dockStrategy = _dockControl.GetViewModel()?.DockStrategy;
if (_dockStrategy == null || _dockStrategy.DockControl.IsLocked)
{
Reset();
return false;
}
FrameworkElement element = null;
IDockTabPane draggedPane = null;
IDockTabItem draggedItem = null;
if (floatWindow != null)
{
// User is dragging a FloatWindow.
// (Note: Dragging of FloatWindows with nested layouts is not supported.)
draggedPane = floatWindow.GetViewModel()?.RootPane as IDockTabPane;
element = floatWindow;
_floatWindow = floatWindow;
_initialSize = floatWindow.RenderSize;
// Start dragging immediately.
_dragDeltaExceeded = true;
}
else if (dockTabItem != null)
{
// User is dragging a DockTabItem in a DockTabPanel.
draggedItem = dockTabItem.GetViewModel();
element = dockTabItem;
_targetDockTabPane = dockTabPane;
_initialSize = dockTabPane.RenderSize;
// Start dragging when threshold is exceeded.
_initialMousePosition = WindowsHelper.GetMousePosition(_dockControl);
_dragDeltaExceeded = false;
}
else if (dockTabPane != null)
{
// User is dragging a DockTabPane.
draggedPane = dockTabPane.GetViewModel();
element = dockTabPane;
_initialSize = dockTabPane.RenderSize;
_initialMousePosition = WindowsHelper.GetMousePosition(_dockControl);
// Start dragging when threshold is exceeded.
_initialMousePosition = WindowsHelper.GetMousePosition(_dockControl);
_dragDeltaExceeded = false;
}
if (draggedPane == null && draggedItem == null)
{
Reset();
return false;
}
// When the user is dragging the FloatWindow, the mouse is captured by Win32 move window
// loop. When dragging a DockTabPane or DockTabItem, the mouse needs to be
// captured to receive mouse events.
if (_floatWindow == null)
{
if (!_dockControl.CaptureMouse())
{
// Failed to capture the mouse.
Reset();
return false;
}
_dockControl.LostMouseCapture += OnLostMouseCapture;
_dockControl.MouseLeftButtonUp += OnMouseLeftButtonUp;
_dockControl.MouseMove += OnMouseMove;
_dockControl.PreviewKeyDown += OnPreviewKeyDown;
if (_targetDockTabPane != null)
_targetDockTabPane.PreviewKeyDown += OnPreviewKeyDown;
}
_dockStrategy.Begin();
if (draggedPane != null)
{
_dockStrategy.Activate(draggedPane);
_activeItem = draggedPane.SelectedItem;
foreach (var item in draggedPane.Items)
if (item.DockState == draggedPane.DockState)
_draggedItems.Add(item);
}
else
{
Debug.Assert(draggedItem != null);
_dockStrategy.Activate(draggedItem);
_activeItem = draggedItem;
_draggedItems.Add(draggedItem);
}
Debug.Assert(_draggedItems.Count > 0);
// Determine whether dragged items may end in a FloatWindow.
_canFloat = CanFloat();
// Store the mouse offset relative to the dragged element.
_mouseOffset = (Vector)WindowsHelper.GetMousePosition(element);
// Remember information needed for a rollback.
ReplaceItemsWithProxies(draggedPane ?? _targetDockTabPane.GetViewModel());
_originalDockState = _draggedItems[0].DockState;
BackupFloatWindowPosition();
// Override mouse cursors. (Mouse cursor should not change to caret over text editor.)
Mouse.OverrideCursor = Cursors.Arrow;
return true;
}