handle no selected file from AppState

Author: MattParkerDev

src/SharpIDE.Godot/IdeRoot.cs

@@ -186,6 +186,12 @@ await this.InvokeDeferredAsync(async () =>
 				_navigationHistoryService.StartRecording();
 				// Select the selected tab
 				var selectedFile = filesToOpen.SingleOrDefault(f => f.isSelected);
+				// If no tab was selected, select the last one (if any) - occurs e.g. when the user last had a decompiled file open, which we currently don't persist to disk, meaning that all other file will have isSelected false
+				if (selectedFile.file is null)
+				{
+					var firstTab = filesToOpen.LastOrDefault();
+					if (firstTab.file is not null) selectedFile = firstTab;
+				}
 				if (selectedFile.file is not null) await GodotGlobalEvents.Instance.FileExternallySelected.InvokeParallelAsync(selectedFile.file, selectedFile.linePosition);
 			});