1. A method for navigating source code, comprising: capturing a program trace data history from a target in response to execution of application executable code on the target device; detecting one or more execution instances from the program trace data history, each execution instance associated with a source code block which is compiled to generate the application executable code; and decorating each source code block on a graphical user interface viewer by displaying, next to a first source code line in a first source code loop block, an execution instance control indicator comprising an interactive drop-down control element to allow selection of a loop iteration for the first source code loop block.