### Issue Summary When typing in the query editor seemingly random keystrokes are duplicated, this makes it almost impossible to use.  ### Technical details: * Redash Version: 5.0.0+b4754 * Browser/OS: Chrome Version 69.0.3497.100 (Official Build) (64-bit) & Firefox 62.0.3 (64-bit). Windows 10 Pro * How did you install Redash: Self hosted running on Kubernetes