Validate Close confirm dialog works as expected

- Issue MatterHackers/MCCentral#2352
Abort dialog has no effect - MatterControl exits

Tests/MatterControl.AutomationTests/PrintingTests.cs

@@ -581,6 +581,17 @@ namespace MatterHackers.MatterControl.Tests.Automation
 					};
 					resetEvent.WaitOne();
 
+					// Click close but cancel
+					testRunner.CloseMatterControlViaUi();
+					testRunner.ClickByName("No Button");
+
+					// Wait for close
+					testRunner.WaitVanishForName("Yes Button", 4);
+					testRunner.Delay(2);
+
+					// Confirm abort
+					Assert.IsFalse(MatterControlApplication.Instance.HasBeenClosed, "Canceling Close dialog should *not* close MatterControl");
+
 					// Close MatterControl and cancel print
 					testRunner.CloseMatterControlViaUi();
 					testRunner.ClickByName("Yes Button");
@@ -588,6 +599,13 @@ namespace MatterHackers.MatterControl.Tests.Automation
 					// Wait for Disconnected CommunicationState which occurs after PrinterConnection.Disable()
 					testRunner.WaitForCommunicationStateDisconnected(maxSeconds: 30);
 
+					// Wait for close
+					testRunner.WaitVanishForName("Yes Button", 4);
+					testRunner.Delay(2);
+
+					// Confirm close
+					Assert.IsTrue(MatterControlApplication.Instance.HasBeenClosed, "Confirming Close dialog *should* close MatterControl");
+
 					// Wait for M106 change
 					testRunner.Delay(() => fanChangedCount > 0, 15, 500);