ReloadAll should not rebuild workspaces

- Issue MatterHackers/MCCentral#4704

MatterControlLib/ApplicationView/ApplicationController.cs

@@ -1711,7 +1711,8 @@ namespace MatterHackers.MatterControl
 
 		public bool IsReloading { get; private set; } = false;
 
-		public async Task ReloadAll()
+		// TODO: No longer contains async child methods. Leaving async compatible pattern in place in case it's needed in the near future, revert back to void if not
+		public Task ReloadAll()
 		{
 			try
 			{
@@ -1745,8 +1746,6 @@ namespace MatterHackers.MatterControl
 						AppContext.RootSystemWindow.AddChild(MainView);
 					}
 				}
-
-				await this.RestoreUserTabs();
 			}
 			catch
 			{
@@ -1757,6 +1756,8 @@ namespace MatterHackers.MatterControl
 			}
 
 			Debug.WriteLine($"LayoutCount: {GuiWidget.LayoutCount:0.0}");
+
+			return Task.CompletedTask;
 		}
 
 		static int reloadCount = 0;
@@ -1926,14 +1927,23 @@ namespace MatterHackers.MatterControl
 			this.Workspaces.Add(workspace);
 		}
 
+
+		private string loadedUserTabs = null;
+
 		public async Task RestoreUserTabs()
 		{
+			// Prevent reload of loaded user
+			if (loadedUserTabs == ProfileManager.Instance.UserName)
+			{
+				return;
+			}
+
+			loadedUserTabs = ProfileManager.Instance.UserName;
+
 			var history = this.Library.PlatingHistory;
 
 			this.Workspaces.Clear();
 
-			// TODO: Loading previous parts/printer is a relatively huge task compared to other startup tasks. These might work better if 
-			// loaded after startup tasks and should have better progress reporting
 			if (File.Exists(ProfileManager.Instance.OpenTabsPath))
 			{
 				try
@@ -3399,6 +3409,7 @@ If you experience adhesion problems, please re-run leveling."
 						await applicationController.Tasks.Execute(task.Title, null, task.Action);
 					}
 
+					// Initial load builds UI elements, then constructs workspace tabs as they're encountered in RestoreUserTabs()
 					await applicationController.RestoreUserTabs();
 
 					if (ApplicationSettings.Instance.get(UserSettingsKey.ShownWelcomeMessage) != "false")

MatterControlLib/PartPreviewWindow/MainViewWidget.cs

@@ -194,6 +194,22 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 
 			tabControl.TabBar.ActionArea.AddChild(brandMenu, 0);
 
+			// Restore active workspace tabs
+			foreach (var workspace in ApplicationController.Instance.Workspaces)
+			{
+				// Create and switch to new printer tab
+				if (workspace.Printer?.Settings.PrinterSelected == true)
+				{
+					tabControl.ActiveTab = this.CreatePrinterTab(workspace, theme);
+				}
+				else
+				{
+					tabControl.ActiveTab = this.CreatePartTab(workspace);
+				}
+
+				tabControl.RefreshTabPointers();
+			}
+
 			tabControl.SelectedTabKey = tabKey;
 
 			statusBar = new Toolbar(theme)

MatterControlLib/SlicerConfiguration/Settings/ProfileManager.cs

@@ -177,6 +177,17 @@ namespace MatterHackers.MatterControl.SlicerConfiguration
 
 			// Wire up the CollectionChanged event
 			Instance.Profiles.CollectionChanged += Profiles_CollectionChanged;
+
+			// Only execute RestoreUserTabs if the application is up and running, never during startup
+			// During startup this behavior must be executed after the MainViewWidget has loaded
+			if (!AppContext.IsLoading)
+			{
+				UiThread.RunOnIdle(() =>
+				{
+					// Delay then load user tabs
+					ApplicationController.Instance.RestoreUserTabs().ConfigureAwait(false);
+				}, .2);
+			}
 		}
 
 		/// <summary>