Brief - feed reading extension for Firefox

When right clicking on a folder and selecting "Mark Folder As Read", it doesn't work, and I get this message in the error console:

Error: targetItem is not defined
Source file: chrome://brief/content/feedlist.js
Line: 610

That's this line:
query.folders = [targetItem.id];

In this function:

markFolderRead: function gContextMenu_markFolderRead() {
var query = new Query();

if (this.targetIsUnreadFolder)
query.unread = true;
else if (this.targetIsStarredFolder)
query.starred = true;
else if (this.targetIsTrashFolder)
query.deleted = ENTRY_STATE_TRASHED;
else
query.folders = [targetItem.id];

query.markEntriesRead(true);
},

Clicking the button in the GUI (top of right pane) when the folder is selected works.