The feature is: The colour of submission status of summary represent what kind of language the person use.
I'm very depressed to know it so lately...
| # | User | Rating |
|---|---|---|
| 1 | Benq | 3676 |
| 2 | Kevin114514 | 3659 |
| 3 | jiangly | 3640 |
| 4 | turmax | 3450 |
| 5 | tourist | 3382 |
| 6 | strapple | 3360 |
| 7 | Um_nik | 3354 |
| 8 | squareOf105 | 3348 |
| 9 | maroonrk | 3312 |
| 10 | idontwannadothis…e | 3191 |
| # | User | Contrib. |
|---|---|---|
| 1 | Qingyu | 155 |
| 2 | nik_exists | 151 |
| 3 | maspy | 149 |
| 4 | AmShZ | 145 |
| 5 | Um_nik | 143 |
| 6 | Errichto | 139 |
| 7 | BledDest | 136 |
| 8 | adamant | 134 |
| 9 | maroonrk | 132 |
| 10 | cry | 130 |
The feature is: The colour of submission status of summary represent what kind of language the person use.
I'm very depressed to know it so lately...
| Name |
|---|



me also don't know it before your post :(
And you can actually configure it in your Arena settings. I think default setup assigns the same color to several languages, which I find misleading.
What about pretty (radio)button ? After near 50 contests i don't know what does it do. When i click on or off nothing changes.
I have always wondered what the buttons are for as well.
"The TopCoder Arena has code-beautification functionality built in for those that wish to use it. In the Room Summary Window, setting Pretty to On in the upper-right corner will cause subsequent source code view to incorporate basic code formatting rules. For some languages and some submissions, the Pretty option will have no effect." — https://community.topcoder.com/tc?module=Static&d1=help&d2=roomSummary
As of now this button has no effect
We can color status of standing by used programming language in Codeforces too. This tool is available here