Clearly mark label set dropdown menu

[FWDekker]

• Gitea version: 1.14.0 (installed using pkg)
• Git version: 2.31.1
• Operating system: FreeBSD 12.2
• Database:
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL: N/A, not a bug)
  • No

Description

The label set dropdown menu does not look like what I expect a dropdown menu to look like, both in the latest version of Firefox and in the latest version of Chrome. It looks like this:

Typically, dropdown menus have some sort of down-pointing arrow on the right to show that the user can click the box to reveal more options. This is something the dependency dropdown menu already has:

The label set dropdown menu does not have that arrow, which makes it look like the default option is the only available option. I sometimes encounter this confusion when I want to apply a label set to my repository, and then get confused about why my own label sets are missing.

I propose that the label set dropdown menu is changed to look something like this: