What does it mean when a listed restore point has a red background?

First, I want to thank you for such an incredibly useful and well written program ( I'm using it on UBUNTU 16.04 LTS and it is working flawlessly). Thank you again for your tireless efforts to provide a MUCH NEEDED program.

I have just 2 questions:

1. I have 5 restore points listed In the "Restore Points" area in the main program window; the oldest three (lowest down the list) each have a "radio" button to its left (the most recent 2 DO NOT have this "radio" button...I'm just wondering why.

2. The 3 oldest restore points in the list are shaded RED...what does this mean? Is something wrong with these backups? As a side note, when I select one of these 3 restore points by clicking the "radio" button beside the entry they also turn RED. Again, I'm just wondering why as I'm a little concerned that they may not work if/when I select them to restore.

Again, thank you for a superior linux program.