Radiant: IP signals are grayed out in Reveal Inserter

Radiant: IP signals are grayed out in Reveal Inserter

Description:
In Radiant, users may see that they are unable to trace some IP signals in Reveal Inserter. It will appear grayed out like the following:
 
Solution:
Please check if the IP you are using has an option to remove Tristate Buffers. If so, check the Remove Tristate Buffer option while configuring the IP. 
 
Here is an example from the I2C Controller IP: