Don't show item context menu until it's ready

With async generation, an incorrect menu was showing first before the
correct version appeared.

chrome/content/zotero/locateMenu.js

@@ -94,8 +94,9 @@ var Zotero_LocateMenu = new function() {
 	 * Clear the bottom part of the context menu and add locate options
 	 * @param {menupopup} menu The menu to add context menu items to
 	 * @param {Boolean} showIcons Whether menu items should have associated icons
+	 * @return {Promise}
 	 */
-	this.buildContextMenu = function(menu, showIcons) {
+	this.buildContextMenu = Zotero.Promise.coroutine(function* (menu, showIcons) {
 		// get selected items
 		var selectedItems = _getSelectedItems();
 		
@@ -103,7 +104,7 @@ var Zotero_LocateMenu = new function() {
 		if(!selectedItems.length || selectedItems.length > 20) return;
 		
 		// add view options
-		_addViewOptions(menu, selectedItems, showIcons);
+		yield _addViewOptions(menu, selectedItems, showIcons);
 		
 		/*// look for locate engines
 		var availableEngines = _getAvailableLocateEngines(selectedItems);
@@ -119,7 +120,7 @@ var Zotero_LocateMenu = new function() {
 			submenu.appendChild(submenuPopup);
 			menu.appendChild(submenu);
 		}*/
-	}
+	});
 	
 	function _addViewOption(selectedItems, optionName, optionObject, showIcons) {
 		var menuitem = _createMenuItem(Zotero.getString("locate."+optionName+".label"),

chrome/content/zotero/zoteroPane.js

@@ -2591,7 +2591,7 @@ var ZoteroPane = new function()
 		}
 		
 		// add locate menu options
-		Zotero_LocateMenu.buildContextMenu(menu, true);
+		yield Zotero_LocateMenu.buildContextMenu(menu, true);
 	});
 	
 	
@@ -2625,12 +2625,25 @@ var ZoteroPane = new function()
 				}
 			}
 		}
-		
-		// Automatically select all equivalent items when clicking on an item
-		// in duplicates view
 		else if (tree.id == 'zotero-items-tree') {
+			// Show context menu once it's ready
+			if (event.button == 2) {
+				// Allow item to be selected first
+				setTimeout(function () {
+					ZoteroPane_Local.buildItemContextMenu()
+					.then(function () {
+						document.getElementById('zotero-itemmenu').openPopup(
+							null, null, event.clientX, event.clientY, true, false, event
+						);
+					})
+				});
+				return;
+			}
+			
 			let collectionTreeRow = ZoteroPane_Local.getCollectionTreeRow();
 			
+			// Automatically select all equivalent items when clicking on an item
+			// in duplicates view
 			if (collectionTreeRow.isDuplicates()) {
 				// Trigger only on primary-button single clicks without modifiers
 				// (so that items can still be selected and deselected manually)

chrome/content/zotero/zoteroPane.xul

@@ -258,7 +258,7 @@
 					<menuitem label="&zotero.toolbar.newCollection.label;" oncommand="ZoteroPane_Local.createCommonsBucket();"/><!--TODO localize -->
 					<menuitem label="Refresh" oncommand="ZoteroPane_Local.refreshCommonsBucket();"/><!--TODO localize -->
 				</menupopup>
-				<menupopup id="zotero-itemmenu" onpopupshowing="ZoteroPane_Local.buildItemContextMenu();">
+				<menupopup id="zotero-itemmenu">
 					<!-- Keep order in sync with buildItemContextMenu -->
 					<menuitem class="menuitem-iconic zotero-menuitem-show-in-library" label="&zotero.items.menu.showInLibrary;" oncommand="ZoteroPane_Local.selectItem(this.parentNode.getAttribute('itemID'), true)"/>
 					<menuseparator/>
@@ -340,7 +340,7 @@
 					<deck id="zotero-items-pane-content" selectedIndex="0" flex="1">
 						<!-- Key navigation is handled by listener in itemTreeView.js -->
 						<tree 
-							id="zotero-items-tree" context="zotero-itemmenu"
+							id="zotero-items-tree"
 							enableColumnDrag="true"
 							disableKeyNavigation="true"
 							onfocus="if (ZoteroPane_Local.itemsView.rowCount &amp;&amp; !ZoteroPane_Local.itemsView.selection.count) { ZoteroPane_Local.itemsView.selection.select(0); }"