"Panorama Scroll Speed" setting doesn't save (resets after relaunch)

Steps to reproduce:

• Open settings
• Change "Panorama Scroll Speed" setting to any value except 100%
• Close the game
• Launch the game

Expected result:

"Panorama Scroll Speed" setting value is still equal to value that you set it to earlier

Actual result:

"Panorama Scroll Speed" setting value is equal to 100% (default value)

Additional notes:

"Panorama Scroll Speed" setting is not present in options.txt file