No one is perfect, errors occur in everyone's GAMS coding. The IDE can help you in finding and fixing those errors. Let's use the example tranerr.gms to illustrate how this occurs. A run of it yields the process window below
wherein the red lines mark errors. To see where the errors occurred lets double click on the top one. A double-click takes you to the place in the source where the error was made. The tip here is always start at the top of the process window when doing this so you find the first error as explained in the error proliferation section of the Compilation Errors chapter.
In this case the error is the spelling of source as sorce and note the IDE cursor as represented by the vertical line in the red box above is placed just at that spot.