I'm using Rapid PHP 2011, Version 11.0.1.127.
I was writing some Javascript inside a .js file with about 3700 lines and a handful of lines exceeding 1000 characters. I typed a function name, "encodeURIComponent(", and continued to type. The documentation bubble for that function came up after a ~1 second delay. The program would then hang for 3-8 seconds while the bubble was displayed.