public IThemeEditorViewModel OpenMasterThemeForScript(IItemFilterScriptViewModel scriptViewModel)
{
var existingMasterThemeViewModelCount =
OpenDocuments.OfType <IThemeEditorViewModel>()
.Count(c => c.IsMasterThemeForScript == scriptViewModel.Script);
if (existingMasterThemeViewModelCount > 0)
{
return(OpenDocuments.OfType <IThemeEditorViewModel>()
.First(c => c.IsMasterThemeForScript == scriptViewModel.Script));
}
return(null);
}