Debug peripheral showing "write-only"

When debugging the Arduino Due, I noticed that some peripheral values are marked as “write-only” and their actual values are not visible. For example, I want to check the value of the CODR register corresponding to the PB15 pin, but I only found a “write-only” label.Is this correct?
If this is normal behavior, what methods can I use in debug mode to check the value of this register?