I had submitted this problem to Infragistics support. I am very happy to say that they provided me with a solution. I just didn't know exactly what properties to go after.

This is supports original code example to resolve the problem:

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

this.ultraDockManager1.ControlPanes[1].DockAreaPane.Size = new Size(730, button1.Top-20);

  ''Me is the form, udm1 is my UltraDockManager
  If Me.udm1.ControlPanes.Count > 0 Then
     Me.udm1.ControlPanes(1).Key = "ug1"
     Me.udm1.ControlPanes("ug1").DockAreaPane.Size = _
        New Size(Me.udm1.ControlPanes(1).DockAreaPane.Size.Width, (Me.Height - 110))
  End If

I put this code in it's own sub and call it from the Form_Load and Form_Resize events.  The check for the ControlPanes.Count > 0 was necessary because of the way I am callinig the form Form_Resize actually gets called before and after Form_Load. Setting the Key property is just something I did for pane reference in later code.

Anyway, works GREAT!!!. Keeps the panes splitter bar the same distance from the bottom of the form during resize, maximize, etc.

Thanks so much Infragistics Support!!!

I am using a dock pane from an UltraDockManager to get the splitter to appear. The image in my previous message was attempting to show what the form looks like at execution time after resizing from the forms original display state.

These are the steps I've taken to create the form:

1. Put an UltraDockManager control on the form.
2. Put an UltraExplorerBar control on the form, dock it to the left with vertical splitter.
3. Put a UltraGrid on the form, dock it to the top with a horizontal splitter.
4. Put a button on the form in the remaining area at the bottom of the form.
   (this is of little consequence, as it's existence has no affect on the position of the horizontal splitter at the bottom of the grid....if the button didn't exist, the splitter still does NOT remain the same distance from the form bottom when the form is resized.

I've seen other people reporting the same issue. Haven't yet seen a solution. In one of those other messages, I've seen your response to be about the order of controls placed on the form and order of their docking. I've attempted that as a resolution, but it did not resolve the issue.

The button is on the form, not in any other child container. If I understand you correctly in 'put the button in this child container' as putting this in another dockareapane, which occupies the bottom portion of the form, this does not resolve my problem. I can anchor the button to the bottom right of the form. I want to do something similar with the splitter bar above the button. Resize fhe form and the splitter bar retains the same distance to the bottom of the form.  

I've reviewed  the classes in the UltraWinDock namespace. and even see some Splitter UI classes, but I don't readily see a way for me to access the correct properties / methods to control the location of the spltterbar. 

I am really hopeful you will be able to provide some insight into resoling this issue.

Thanks

Lonnie