@ericsfraga I don't use FlySpell, but FireFox is my main browser, too. But then wouldn't killing all my Firefox buffers probably fix the lag? I have tried that; I wonder if they make some additions to the WM state (is that even a thing?). I have also noticed if I leave them open and connected to a long running REPL for browser-interactive developing it can cause problems, but I chalk that up to a process getting long in the tooth in its browser usage..