Debugging in Blender. Where to see errors?

Hi guys.
Unfortunately i have not found answer to my question in web. Problem is… I am writing add-on, but when i have some errors in code i got message “Error in Python script. Look for detailed information in console”. Problem is that console opened, but i dont get any error messages there, so i have to guess where is error. Blender version is 2.76. What should i do to get errors in console window when i run add-on?

Thank you.