The first thing I noticed from your attached photo is that you have not declared the label segment you want to jump into…. In fact you have declared no LBL sections at all and I strongly believe this is the reason why you can’t move and modify that segment of the command. Try declaring a LBL[5] further down your program with a dummy instruction like R[10] = 0. Now the TP should let you navigate to the LBL portion of your skip command.
You can always install a trial version of roboguide, create an exact copy of your existing robot, and make some tests in there like:
Create a routine-like program with the skip condition and the high-speed skip instruction using the virtual teach pendant, what happens?
Try to upload that program to your controller, what happens? Are you able to modify the label?
Write the program in roboguide’s text editor then compile and load to the controller. What happens?