8. A computer-readable storage memory configured with data and with instructions that when executed by at least one processor causes the processor(s) to perform a technical process for troubleshooting an executing application program, the technical process comprising the steps of: modifying a property of a visual construct of an application visual of the application program while the application program is executing and without pausing execution of the application program, thereby creating a property modification, the visual construct being defined by a markup; identifying source code to be altered by using a markup annotation which correlates the visual construct with a portion of the markup representing the visual construct; troubleshooting a transient expression in the markup while the application program is executing, by using a pre-evaluation version of the transient expression that was subsequently replaced by an evaluated version while the application program is executing; and persisting the property modification into a source code alteration of the application program while the application program is executing, without pausing execution of the application program, and after the step of identifying source code to be altered.
8. A computer-readable storage memory configured with data and with instructions that when executed by at least one processor causes the processor(s) to perform a technical process for troubleshooting an executing application program, the technical process comprising the steps of: modifying a property of a visual construct of an application visual of the application program while the application program is executing and without pausing execution of the application program, thereby creating a property modification, the visual construct being defined by a markup; identifying source code to be altered by using a markup annotation which correlates the visual construct with a portion of the markup representing the visual construct; troubleshooting a transient expression in the markup while the application program is executing, by using a pre-evaluation version of the transient expression that was subsequently replaced by an evaluated version while the application program is executing; and persisting the property modification into a source code alteration of the application program while the application program is executing, without pausing execution of the application program, and after the step of identifying source code to be altered. 13. The computer-readable storage memory of claim 8 , wherein the technical process further comprises operating at least one of the following tools concurrently and independently of a live authoring diagnostics round trip module (“LADRT module”), in that LADRT module functionality does not require the presence of the tool and tool functionality does not require the presence of the LADRT module: a debugger tool; a source code editor tool.