Came across this randomly. I was deleting some art assets in the game sidebar by right clicking them and choosing delete. Every time I deleted something I was given a notification window asking if I was sure I wanted to delete the item. I got a little tired of this, and clicked the button "prevent this dialog box from opening again." After that, I could not delete items. I'd use the right click menu to delete, and nothing would happen. I re-enabled the notification window through the chrome settings (you can do this in advanced setting/privacy-content setting), restarted the browser, and it worked fine afterwards.