All of my ultrawingrids were within ultrapanels within user controls.  The user controls are selected by an ultratoolbarmanager and ribbon and are displayed in a main panel. All user controls are added at run time.  I had to change out all of the ultrapanels to standard panels which appeared to dock properly and manually resized and positioned  the ultrawingrids within the panels.  This fixed almost all of the issues except when restoring the application from it's minimized state.  Fighting this and coding around the issue, I now believe all of the problems might be an issue with the ribbon height sequencing.  I found that the control  _frmMain_Toolbars_Dock_Area_Top height was not always the same (140) during the resizing events.  The code around was to add the following sequence to the main form resize:

Private Sub frmMain_Resize(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Resize

        Try

            PanelMain.Location = New Point(3, 140)

            PanelMain.Height = Me.Height - 144

            PanelMain.Width = Me.Width - 8

And after initializing all user controls whose visibility is controlled by the ribbon tools, I then kick the resize method with a :

Me.Width = Me.Width - 1

Again, all of these resizing issues only appeared after upgradding from version 10.3.20103.1000 to 10.3.20103.2607.  I did try turning the UltraWinGrids dock fill back on but they again failed to paint correctly 100% of the time on resizes. 

If any of you guys can get a simple sample project attached demonstrating some odd behavior I'll take a look at it and get the bug submitted if necessary.

The original poster had a project attached, but his sample really didn't work out to a bug. The anchors were set incorrectly.

Unfortuneately I upgraded from 10.3.20103.1000 to 10.3.20103.2607 and I am having the same issues with the Anchor and Dock fill not working for UltraPanels and UltraWinGrids.  I ended up coding around the issue by changing the dock to none adding code to all of the resizing events such as the following: 

Private Sub UltraPanelTop_Resize(sender As System.Object, e As System.EventArgs) Handles  UltraPanelTop.Resize

  UltraGrid1.Location = New Point (0, PanelTopTop.Height)

  UltraGrid1.Width = UltraPanelTop.Width

  UltraGrid1.Height = CInt (IIf(UltraPanelTop.Height - PanelTopTop.Height > 0, UltraPanelTop.Height - PanelTopTop.Height, 0))

End Sub

anybody from Infragistics team?

Support Request  CAS-60914-P6DNGM.

with 10.3.20103.2067 BUG still reproducible!

someone can fix it???!!!