Reproducible at https://try.gitea.io (currently dbb4aee).

Description

• Issue titles can consist of just spaces. Such issues cannot be selected in the issue list.
• Wiki page titles can consist of just spaces. Such pages cannot be selected in the wiki tab.
• Pull request titles can consist of just spaces. Such pull requests cannot be selected in the pull request tab.