Lunar Porter put a fuel gauge up and never took it away, so the shell came
back with FUEL across the top and the cursor underneath. Clearing did not
help: a window is a layer at a SCREEN position that does not scroll, which
is exactly what makes one left behind unpleasant - it sits over whatever
comes next and cannot be scrolled off, cleared away or typed past.
Taken away rather than given back, like the sprite table and for the same
reason: nothing the shell draws is a window, so there is nothing to
restore. And a program that FAULTED while one was up could not have taken
it down itself, which is why this belongs to the system rather than to
whichever programs remember.
The check for it needed writing twice, and the first version was the
familiar kind of wrong. It counted the gauge BAR's colour - and the bar
disappears on its own whatever happens, because it is drawn with a tile
the screen save puts back, so the check passed with the teardown deleted.
What actually survives is the LABEL, in font tiles the shell needs anyway.
So the screen is cleared afterwards and read cell by cell. With the window
down a cleared row is "> " and a cursor; with it up the same row is F, U,
E, L. Cells one and three being empty is the whole difference, and it is
29 and 22 pixels of it rather than a threshold somebody has to believe.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
AnachronautandClaude Opus 5
6073086584