missing top menu for thunderbird, plus TypeError in console

I just perceived my thunderbird misses the top menu bar, that one above the tabs area. I've already tried entering in safe mode, disabling everything; tried the right click menu and disabled the menu, enabling it shortly thereafter. However, none of that brought back the menu bar. Executing thunderbird in console, I've got the following messages: ************************* A coding exception was thrown and uncaught in a Task. Full message: TypeError: searchSettings[region] is undefined Full stack: SRCH_SVC_parseListJSON@resource://gre/components/nsSearchService.js:3686:7 SearchService.prototype._asyncFindJAREngines<@resource://gre/components/nsSearchService.js:3630:7 TaskImpl_run@resource://gre/modules/Task.jsm:319:42 Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:932:23 this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:813:7 this.PromiseWalker.scheduleWalkerLoop/<@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:747:11 ************************* ************************* A coding exception was thrown and uncaught in a Task. Full message: TypeError: searchSettings[region] is undefined Full stack: SRCH_SVC_parseListJSON@resource://gre/components/nsSearchService.js:3686:7 SearchService.prototype._asyncFindJAREngines<@resource://gre/components/nsSearchService.js:3630:7 TaskImpl_run@resource://gre/modules/Task.jsm:319:42 Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:932:23 this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:813:7 this.PromiseWalker.scheduleWalkerLoop/<@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:747:11 ************************* I would like to avoid deleting the .thunderbird directory, but I have no clue and didn't find anything much alike this. I tried aptitude reinstall thunderbird, but without success.