Allow dock items above dock item with "GroupOnlyById" to attach to the root

[izaksuilov]

Now if you have dock with "GroupOnlyById", other docks that are above this one can't attach even to the root (top, right, bottom and left positions).

For example, "Floating Window - Hi" can attach to the bottom if it's above Dock Item "Hello" which doesn't have GroupOnlyById.

But if I want to attach this floating window to the bottom, the button disapears because the bottom Tabbed Group has GroupOnlyById.

I suggest to always allow to attach to the root like this

For that I suugest to replace existing code at NP.Avalonia.UniDock.DockManager:

NP.Avalonia.UniDock/src/DockManager.cs

Lines 359 to 384 in 70ed1e2

	private void OnPointerMoved(Point2D pointerScreenLocation)
	{
	if (_currentDockGroups == null)
	{
	return;
	}
	var pointerAboveGroups =
	_currentDockGroups
	.Where(gr => gr.Group.IsVisible && gr.Rect.ContainsPoint(pointerScreenLocation))
	.Select(gr => gr.Group);
	CurrentLeafObjToInsertWithRespectTo = pointerAboveGroups.FirstOrDefault();
	var rootDockGroup = CurrentLeafObjToInsertWithRespectTo?.GetDockGroupRoot() as RootDockGroup;
	if ((CurrentLeafObjToInsertWithRespectTo != null) &&
	(CurrentLeafObjToInsertWithRespectTo is not RootDockGroup) &&
	rootDockGroup?.GroupOnlyById == DraggedWindow?.GroupOnlyById)
	{
	CurrentRootDockGroup = rootDockGroup;
	}
	else
	{
	CurrentRootDockGroup = null;
	}
	}

With this code:

private void OnPointerMoved(Point2D pointerScreenLocation)
{
    if (_currentDockGroups == null)
    {
        CurrentLeafObjToInsertWithRespectTo = null;
    }
    else
    {
        var pointerAboveGroups =
            _currentDockGroups
                .Where(gr => gr.Group.IsVisible && gr.Rect.ContainsPoint(pointerScreenLocation))
                .OrderBy(gr => gr.Group.GetGroupWindow() != null)
                .Select(gr => gr.Group);

        CurrentLeafObjToInsertWithRespectTo = pointerAboveGroups.LastOrDefault();
    }

    RootDockGroup? rootDockGroup = null;

    if (CurrentLeafObjToInsertWithRespectTo != null && CurrentLeafObjToInsertWithRespectTo is not RootDockGroup)
    {
        rootDockGroup = CurrentLeafObjToInsertWithRespectTo?.GetDockGroupRoot() as RootDockGroup;
    }
    else if (CurrentLeafObjToInsertWithRespectTo == null && _rootGroups != null)
    {
        var pointerAboveRoots =
            _rootGroups
                .Where(gr => gr.Group.IsVisible && gr.Rect.ContainsPoint(pointerScreenLocation))
                .OrderBy(gr => gr.Group.GetGroupWindow() != null)
                .Select(gr => gr.Group);
        rootDockGroup = pointerAboveRoots.LastOrDefault();
    }

    CurrentRootDockGroup = rootDockGroup?.GroupOnlyById == DraggedWindow?.GroupOnlyById ? rootDockGroup : null;
}