WPF Button disables itself without binding or code making it so

Question

I'll give some details below, but briefly I have a problem wherein a button in my WPF application will disable itself if I click somewhere else in the application. This button is linked to a Command but there is absolutely NOTHING bound to the IsEnabled property of the button and the Command CanExecute callback just sets e.CanExecute to true.

I saw this similar SO question (Weird problem where Button does not get re-enabled unless the mouse is clicked) but it was not helpful.

The application is simple and consists of a DockPanel divided into 4 parts. The left section contains a DataGrid and the right section contains a UserControl that also contains a couple DataGrids as well as the offending Button. It's so weird, but if I click on any row in the left DataGrid, the Button in the right section becomes disabled. The only way I can then re-enable it is to click on any row in either of the DataGrids in the right section!

Again, there IS absolutely nothing bound to the IsEnabled property of the button or any other code/markup implicitly in place that would allow this to happen.

Some relevant code snippets:

UserControl Command bindings:

<UserControl.CommandBindings>
    <CommandBinding Command="cmd:DBScriptCommands.LoadScripts" CanExecute="cmdLoadScripts_CanExecute" Executed="cmdLoadScripts_Executed" />
    <CommandBinding Command="cmd:DBScriptCommands.RunScripts" CanExecute="cmdRunScripts_CanExecute" Executed="cmdRunScripts_Executed" />
</UserControl.CommandBindings>

Button xaml:

<Button IsEnabled="True" x:Name="btnLoadScripts" Command="cmd:DBScriptCommands.LoadScripts">
    <StackPanel HorizontalAlignment="Stretch">
        <Image Source="/Images/folder-open.png" />
        <TextBlock>Load Scripts</TextBlock>
    </StackPanel>
</Button>

CanExecute for Command:

    private void cmdLoadScripts_CanExecute(object sender, CanExecuteRoutedEventArgs e)
    {
        e.CanExecute = true;
    }

This has me baffled and any ideas are appreciated. If more information is needed, please let me know.

Edit 1: Seems like it is something to do with the Command (still not sure what) - if I remove the Command parameter from the Button, the problem goes away - not useful because I want the button to trigger the Command, but interesting. In the CanExecute(), if I set e.CanExecute to false, the button is always disabled which makes sense. When it is set to true (like it is now) then I have the problem I've describe where it seems like something is setting it to false by magic sometimes.

Thanks