You can still use debugger but your app window must be open on second screen...
Well, that solves one problem.
But another one is that often some place in the code has to be performed 1000 times before something interesting happens. In that case, LOGs and Find (in the LOG file) are best option.
Yet another, more or less C++ problem is that debuggers are good for dumping simple values. But when dealing with complex C++ structures, it is often difficult.