tools: add tooltips to ProjectsList

tools/level_editor/panel_projects_list.vala

@@ -44,6 +44,7 @@ public class ProjectRow : Gtk.ListBoxRow
 		_hbox.pack_start(_vbox);
 
 		_remove_button = new Gtk.Button.from_icon_name("list-remove-symbolic");
+		_remove_button.set_tooltip_text("Remove the project from the list.");
 		_remove_button.get_style_context().add_class("flat");
 		_remove_button.get_style_context().add_class("destructive-action");
 		_remove_button.set_halign(Gtk.Align.CENTER);
@@ -52,6 +53,7 @@ public class ProjectRow : Gtk.ListBoxRow
 		_hbox.pack_end(_remove_button, false, false, 0);
 
 		_open_button = new Gtk.Button.with_label("Open");
+		_open_button.set_tooltip_text("Open the project.");
 		_open_button.get_style_context().add_class("flat");
 		_open_button.set_halign(Gtk.Align.CENTER);
 		_open_button.set_valign(Gtk.Align.CENTER);
@@ -129,9 +131,11 @@ public class ProjectsList : Gtk.Box
 			});
 
 		_button_import_project = new Gtk.Button.with_label("Import...");
+		_button_import_project.set_tooltip_text("Import an existing project.");
 		_button_import_project.action_name = "app.add-project";
 
 		_button_new_project = new Gtk.Button.with_label("Create New");
+		_button_new_project.set_tooltip_text("Create a new project.");
 		_button_new_project.get_style_context().add_class("suggested-action");
 		_button_new_project.action_name = "app.new-project";