I have noticed that sometimes when stepping through ADF code in the debugger, there is a long lag of 2-5 seconds each time I step. Other times it is snappy and I can quickly step over each line of code with no delay. I recently discovered that this lag is caused by having the ADF Structure Panel visible (See Image). This panel in the lower left corner contains some useful information if you need to look at it but if visible it takes a long time to refresh each time you stop at a breakpoint,. So to speed up your debugging simply switch to another tab so that the ADF structure Panel is not visible and you can step through code a whole lot smoother. You may not notice this if you have a simple structure but our page had a number of nested regions that was causing delays when stepping through code.