Accerator not firing on form

Are there any things that will interfere with an ESC key accelerator firing on a form? I am making most forms close by ESC doing this:

private void frmEditIssue_Accelerator(object sender, AcceleratorEventArgs e)
{
if (e.KeyCode == Keys.Escape)
{
RequestFormClose();
}
}

and registering the accelerator in the designer.

This is working on most forms, but not one of them — the event never fires.

The accelerator key IS present on the form at runtime.