Thanks for your reply, Johan. I'm not sure what caused this. As best I recall, it was working last night when I went to bed and today it is not. The only unusual thing I recall doing late last night was importing the XMLSupport library. I haven't used it yet, this is just preparation for future tasks. Of course I also worked on some code and ran tests, but this to me is fairly normal and unlikely to cause problems. The program I'm working on fetches HTML or JSON data from a url, parses it with NeoJSON (or manually in the case of HTML), and produces a text file in a tab-delimited format based on the parsed data. Nothing I have done since I first installed Pharo has anything to do with the GUI system and the only packages I've installed are NeoJSON, NeoCSV, and XMLSupport. I have three windows open. A workspace, a transcript and a browser. I tend to keep the same windows up all the time so all three are long-lived windows if that seems relevant. If I create a new window of any of the three types, they seem to behave normally. Based on your comment that a right-click in the background *should* bring up the World menu, it sounds like the bug must be something to do with which window receives and processes the click event. If there is any diagnostic I can run to help gather more data just let me know and I will be glad to run it and post the results. In the meantime, is there a way (perhaps through keyboard shortcuts or something) to go through the list of open windows, select them, and close them? Or even to do a a "close all windows"? I ask because it seems like new windows behave correctly so maybe if I can kill off the misbehaving ones that will solve the issue. I can also open a new Workspace and paste in any code to collect info or close the windows. Or finally, if we cannot find a way to recover things properly then I suppose I could learn how to file out my code and start again with a fresh installation, redoing the installs of the couple of libraries I've added. -- View this message in context: http://forum.world.st/Left-mouse-button-not-working-in-Pharo-3-0-tp4795107p4... Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.