After things were for a long time working swimmingly, something must have "slipped". Suddenly, without warning, when I open an IVF Solution (*.sln), the IDE comes up and the f90 source file names appear in the Solution Explorer panel (upper right-hand corner). But they no longer load automatically. I have to individually click them one at a time to load them into the main pane. Earlier, they'd load automatically when the SLN was opened.
What toggle did I accidentally hit?