filebrowser: block events when opening folder takes too long
Whenever I try to open a large folder (e.g. the Data folder of the current excercise) online, opening the directory takes a while but the user does not get any information on this process. When clicking on the folder again, while it is opening, a directory that does not exist is opened because the directory is simply chained to the previous one (see screenshot).
Suggestion: block all events while loading/opening directories
(from redmine: issue id 1956, created on 2014-10-26 by root, closed on 2015-09-18)