We use markText to interactively highlight multiple lines of SQL code. See demo here -- https://app.sqldep.com/queryscope/demo/
You can notice a small delay when you move the cursor over multiple columns. With larger chunk of SQL queries the delay arises to multiple seconds and our app becomes barely usable.
Is there a way how we can improve performance? We are fine with making a donation if the Code Mirror performance is improved significantly.