To reproduce:
1. Enter the `d`esignation menu
2. Press `-+` to change priorities
3. Create a designation
4. Press `Alt-p` to hide priorities
5. Exit and re-enter the designation menu (`Esc`, `d`)
Previously, priorities would be visible again after step 5. With this change, they are not visible until you press `Alt-p` again.
Fixes#1068. Note that this is a relatively unobtrusive fix: selecting a priority with `+-` will still result in priorities being shown again. This is native DF behavior that I am reluctant to override because users of designation priorities likely want to see them.
lethosor