A small error in RM 4.0

I have a trigger event, to go on at 10pm on Mon,Tues,Wed, Thu.
I edit the trigger to add Sunday to the list.

It just doesn't take it.
Here are the before and after pictures.

After selecting Sunday, click anywhere on the page with open white space. Then click Done Setting Schedule. I have had similar things happen when checking a box and immediately clicking Done without first clicking somewhere else on the page.

When I did your suggestion it allowed me to put in a new, separate time for the Sunday entry. So, I put in a new time, and went on.
I'm not sure if this is an "error", or I just didn't understand the User Interface in the first place.
Regardless, thank you @stephack

I dont think it's so much an error as it is a limitation of using a web browser for the interface. Some settings require a loss of focus to set themselves. You will see this in many apps and is one of the reasons you will see the "update" button throughout a lot of built in HE apps....at least this is my limited understanding of how the UI operates... I'm no webdev...and I'm sure @patrick could explain it better than I have.