Sampat Kumar
Ansys Employee

Hi All, 
This was the bug and it is resolved in the 2023R2. 
Edit the system environment variables in the search window of your system, then click environment variable, select a new user variable in the user variable, type the variable name ANS_USE_OPENGL_LEGEND_EDIT, and set the variable value =1 Then apply this setting in the system.
I would recommend to restart the system and then open it. You will be able to edit it on your system. 

I have provided the workaround above that can also help you 
workaround- "Double click on the number and enter the number, Although you will not be able to see the mouse cursor and the number when you enter, even after entering the number, press the Enter button, and you can see the number change. If this is not working, then try to do right-click on the number and click on Edit, then enter the number, then press the Enter button from the keyword, and the value will change."