After wasting hours on this, following on the heels of my Last Problem, I'm starting to feel that Framework 4 is a master of subtle evil, or my PC is haunted.

I have three comboboxes and a textbox on a WPF form, and I have an out-of-the-box Subsonic 3 ActiveRecord DAL. When I load this "edit record" form, the comboboxes fill correctly, they select the correct items, and the textbox has the correct text. I can change the TextBox text and save the record just fine, but the comboboxes CANNOT BE CHANGED. The lists drop down and highlight, but when you click on an item, the item selected stays the same.

Here's my XAML:

        <StackPanel Orientation="Horizontal" Margin="10,10,0,0">
            <TextBlock Width="80">Asset</TextBlock>
            <ComboBox Name="cboAsset" Width="180"  
              DisplayMemberPath="AssetName"
              SelectedValuePath="AssetID" 
              SelectedValue="{Binding AssetID}" ></ComboBox>
        </StackPanel>
        <StackPanel Orientation="Horizontal" Margin="10,10,0,0">
            <TextBlock Width="80">Status</TextBlock>
            <ComboBox Name="cboStatus" Width="180" 
              DisplayMemberPath="JobStatusDesc"  SelectedValuePath="JobStatusID"  
              SelectedValue="{Binding JobStatusID}" ></ComboBox>
        </StackPanel>
        <StackPanel Orientation="Horizontal" Margin="10,10,0,0">
            <TextBlock Width="80">Category</TextBlock>
            <ComboBox Name="cboCategories" Width="180" 
              DisplayMemberPath="CategoryName"
              SelectedValuePath="JobCategoryID"
              SelectedValue="{Binding JobCategoryID}" ></ComboBox>
        </StackPanel>
        <StackPanel Orientation="Horizontal" Margin="10,10,0,0">
            <TextBlock Width="80">Reason</TextBlock>
            <TextBox Name="txtReason" Width="380" Text="{Binding Reason}"/>
        </StackPanel>

Here are the relevant snips of my code (intJobID is passed in):

    SvcMgrDAL.Job oJob;
    IQueryable<SvcMgrDAL.JobCategory> oCategories = SvcMgrDAL.JobCategory.All().OrderBy(x => x.CategoryName);
    IQueryable<SvcMgrDAL.Asset> oAssets = SvcMgrDAL.Asset.All().OrderBy(x => x.AssetName);
    IQueryable<SvcMgrDAL.JobStatus> oStatus = SvcMgrDAL.JobStatus.All();

        cboCategories.ItemsSource = oCategories;
        cboStatus.ItemsSource = oStatus;
        cboAsset.ItemsSource = oAssets;
        this.JobID = intJobID;
        oJob = SvcMgrDAL.Job.SingleOrDefault(x => x.JobID == intJobID);
        this.DataContext = oJob;

Things I've tried:

-Explicitly setting IsReadOnly="false" and IsSynchronizedWithCurrentItem="True"
-Changing the combobox ItemSources from IQueryables to Lists.
-Building my own Job object (plain vanilla entity class).
-Every binding mode for the comboboxes.

The Subsonic DAL doesn't implement INotifyPropertyChanged, but I don't see as it'd need to for simple binding like this. I just want to be able to pick something from the dropdown and save it.

Comparing it with my last problem (link at the top of this message), I seem to have something really wierd with data sources going on. Maybe it's a Subsonic thing?