ChooseProjectButton: prevent duplicate projects in dropdown

src/FolderManager/Item.vala

@@ -51,6 +51,10 @@ namespace Scratch.FolderManager {
             file.rename (new_name);
         }
 
+        public bool equal (Item b) {
+            return path == b.path;
+        }
+
         public void trash () {
             file.trash ();
         }

src/Services/GitManager.vala

@@ -51,8 +51,19 @@ namespace Scratch.Services {
         }
 
         public MonitoredRepository? add_project (FolderManager.ProjectFolderItem root_folder) {
-            var root_path = root_folder.file.file.get_path ();
+            var root_path = root_folder.path;
             MonitoredRepository? monitored_repo = null;
+            uint position;
+            if (project_liststore.find_with_equal_func (
+                    root_folder,
+                    (a, b) => { return ((FolderManager.Item) a).equal ((FolderManager.Item) b); },
+                    out position
+                )) {
+
+                var repo = project_gitrepo_map.@get (root_path);
+                return repo;
+            }
+
             try {
                 var git_repo = Ggit.Repository.open (root_folder.file.file);
                 if (!project_gitrepo_map.has_key (root_path)) {

src/Widgets/ChooseProjectButton.vala

@@ -99,7 +99,16 @@ public class Code.ChooseProjectButton : Gtk.MenuButton {
 
         popover = project_popover;
 
+        // Initialise with any pre-existing projects (needed for second and subsequent window)
         var git_manager = Scratch.Services.GitManager.get_instance ();
+        var src = git_manager.project_liststore;
+        for (int index = 0; index < src.n_items; index++) {
+            var item = src.get_object (index);
+            if (item is Scratch.FolderManager.ProjectFolderItem) {
+                var row = create_project_row ((Scratch.FolderManager.ProjectFolderItem)item);
+                project_listbox.insert (row, index);
+            }
+        }
 
         git_manager.project_liststore.items_changed.connect ((src, pos, n_removed, n_added) => {
             var rows = project_listbox.get_children ();