1. Launch Xcode
2. Select File->Open Recent->Clear Menu
3. Right-click the Xcode icon and select Show All Windows. You should now see only your current document in the recents list at the bottom
4. Quit Xcode.
   The recents list should now only be populated with your single current project.

remove xcode recent projects from dock menu 移除xcode dock菜单显示的项目列表