Just had to reboot because of some message in Pd about input being grabbed. At that point: keyboard was dead. All other app menus were dead, except the system menu with the reboot option.
I apologize that I couldn't copy/paste the error text because 1/ ctrl-c obviously dead (keyboard inactive); 2/ RMC in the Tk error window was inactive; 3/ I couldn't even copy/paste a temp filename from any other app to save it.
Why does this happen and how to prevent it?
Sorry but it's quite upsetting to be in the middle of something and Tk breaks user input globally.