I did try to re-enforce the crack area with a 4" x 1/2" strip of metal
with 4 holes & 4 screws. It kinda helps but not much. After looking a
friend's home built by a reputable builder, I figured it out. Near the
top is a horizontal support bar that fits the whole width, screwed to
the 4 vertical beams. That definitely keeps the top section straight.
Guess the idiot who originally installed the garage wasn't really a
professional. The door is only 2 years old and already bent so I figure
even if I replace it with a new piece, it will bend soon or later
without the extra support bar. Now it's just a matter of finding a
similar bar ...