Wing can open files in several modes that control how and when files are closed:
Transient Mode -- Files opened when debugging or navigating to point of definition are opened in transient mode and will be automatically closed when hidden.
Sticky Mode -- Files opened from the File menu or from the keyboard file selector will be opened in sticky mode, and are kept open until they are explicitly closed.
A file can be switched between these modes by clicking on the stick pin icon in the upper right of the editor area.
Right-click on the stick pin icon to navigate to files that were recently visited in the associated editor or editor split. Blue items in the menu were visited in transient state and black items were sticky. Note that this differs from the Recent area in the File menu, which lists only sticky file visits and includes visits for all editors and editor splits.
Transient files that are edited are also automatically converted to sticky mode.