Hello,
I'm using Renesas RH850 - RH850/C1M-A2
Since you are not using NXP product I will answer only generally.
whenever microcontroller power is turned off and turned on back the debugger window is stuck.
I am not sure what you mean by the sentence above. The GIU is stuck or you debugger is not attached to running target after POR?
After POR you need to attach debugger to micro to put it in debug mode again.
You can do such using debugger scripts, on some advanced debuggers.
Also for third party products, please get in touch directly with product manufacturer support.
Best regards,
Peter