When debugging has stopped at some location in the robot, you can switch back to design mode at the same location by clicking the icon in debug mode. This allows you to closer examine that location in design mode, and perhaps modify the steps around that location, or modify some other part of the robot.
You can also switch to design mode and go to the location where a value was returned. To do this, select the value in the "Output" panel in the "Input/Output" tab and click the "Goto" button in the lower right corner of the tab. This is useful if a value has not been extracted correctly, and you want to find out why.
You can also switch to design mode and go to the location where an API exception was reported, or where an error occurred. When you view an API exception in the "API Exceptions" tab or the "API Exception" sub-tab in the "State" tab, you can click the "Goto" button to the right of the location code to go to the location where the API exception was generated. You can also click on a "Goto" button to the right of a specific error to go to the location where that error occurred. This is, of course, very useful when you want to find the reason for the error and fix the problem.
When you have done what you want in design mode, you can resume the debugging. If you haven't modified the robot, you can simply click the icon. If you have modified the robot, the debugging will have been automatically restarted, so you cannot resume it directly. Instead, you can start a new debugging session from the current location in design mode by clicking the icon.