Null reference errors in the designer

i'm having an issue with the Docking controls, which i'm about 15 days into evaluating. i was wondering if there's something wrong here or if i did something.

Here's the issue i'm seeing:

1. Hide Call Stack

at ActiproSoftware.UIStudio.Dock.DockManager.EndInitialization()
at ActiproSoftware.UIStudio.Dock.Design.DockManagerDesigner.#Xcf(Object #xhb, EventArgs #yhb)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at System.ComponentModel.Design.DesignerHost.OnLoadComplete(EventArgs e)
at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.Serialization.IDesignerLoaderHost.EndLoad(String rootClassName, Boolean successful, ICollection errorCollection)
at System.ComponentModel.Design.Serialization.BasicDesignerLoader.OnEndLoad(Boolean successful, ICollection errors)
at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.OnEndLoad(Boolean successful, ICollection errors)
at System.ComponentModel.Design.Serialization.BasicDesignerLoader.System.ComponentModel.Design.Serialization.IDesignerLoaderService.DependentLoadComplete(Boolean successful, ICollection errorCollection)
at System.ComponentModel.Design.Serialization.BasicDesignerLoader.BeginLoad(IDesignerLoaderHost host)
at System.ComponentModel.Design.DesignerHost.BeginLoad(DesignerLoader loader)

i see this issue after making a ToolWindow dock-able in the designer after it has been running in Auto-Hide.

i may have made a bad merge of a resx file or the designer, but before tweaking this property, everything builds, displays, and runs correctly.

Any ideas?