Now that the test application is passing its runtime startup, it’s attempting to initialize various Toolbox managers, which of course gives us a good excuse to start work on the Menu and Window Managers, beginning from InitWindows.

The menu bar and desktop are some of the most iconic parts of the Mac user interface, and as these initialization routines set up these, we have something that is finally stating to look like a real Mac desktop. Another benefit of having file system at this point is that we can actually read the desktop pattern from ‘PAT ‘ resource ID 16 (using new GetPattern trap) from System file, like a real Mac does, and use that to paint the desktop.

Another interesting new feature was the support of virtual code resources read from the System file, using a customized mixed-mode loading mechanism which allows inserting UPP record for a native C code resource, such as in this case MBDF, into the MBDF resource read from the System file – which in this case was used to draw the menu bar!