Fix node not being registered with the asset after undoing it's delet…

…ion (#74)

Source/FlowEditor/Private/Asset/FlowAssetEditor.cpp

@@ -673,6 +673,7 @@ void FFlowAssetEditor::DeleteSelectedNodes()
 {
 	const FScopedTransaction Transaction(LOCTEXT("DeleteSelectedNode", "Delete Selected Node"));
 	FocusedGraphEditor->GetCurrentGraph()->Modify();
+	FlowAsset->Modify();
 
 	const FGraphPanelSelectionSet SelectedNodes = FocusedGraphEditor->GetSelectedNodes();
 	SetUISelectionState(NAME_None);