Exception: TypeError: aFolder is undefined gloda_ds_mapFolderURI((void 0))@file:///Users/skywalker/objdir-tb/mozilla/dist/ShredderDebug.app/Contents/MacOS/modules/gloda/datastore.js:1445 gloda_ns_getFolderForFolder((void 0))@file:///Users/skywalker/objdir-tb/mozilla/dist/ShredderDebug.app/Contents/MacOS/modules/gloda/gloda.js:328 ([object Object])@chrome://experimentaltoolbar/content/overlay.js:97 setTabTitle([object Object])@chrome://messenger/content/tabmail.xml:725 FolderDisplayWidget_show([object XPCWrappedNative_NoHelper])@chrome://messenger/content/folderDisplay.js:511 ([object XPCWrappedNative_NoHelper])@file:///Users/skywalker/objdir-tb/mozilla/dist/ShredderDebug.app/Contents/MacOS/modules/traceHelper.js:121 FolderPaneSelectionChange()@chrome://messenger/content/commandglue.js:352 onselect([object Event])@chrome://messenger/content/messenger.xul:1 select(69)@:0 onxblmousedown([object MouseEvent])@chrome://global/content/bindings/tree.xml:975 Change from one inbox to another and this error appears in console in red, with a Mac debug build compiled with the v9 patch in bug 474701. Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1pre) Gecko/20090610 Lightning/1.0pre Shredder/3.0b3pre

This looks like a problem in exptoolbar. Hoisted by my own petard, if you will. Suggesting disabling exptoolbar for the time being. It has all sorts of issues.