public AppOverlayViewModel(UserSettings settings, IDialogManager dialogManager)
{
DisplayName = "External Apps";
_userSettings = settings;
_dialogManager = dialogManager;
this.SetCommand(x => x.AddAppCommand).RegisterAsyncTask(AddApp).Subscribe();
this.SetCommand(x => x.RemoveAppCommand).Subscribe(x => RemoveApp((ExternalApp)x));
ExternalApps.EnableCollectionSynchronization(_externalAppsLock);
}