Have others found LCD panels susceptible to image burn-in?

A couple days ago, I noticed a "ghost" of a text window that was
underneath another window. I moved the two windows out of the
way and noticed that the "ghost" was still visible on the desktop.
The odd thing is that only a portion of the text window was
"burned" into the panel, even though the panel was displaying the
entire window in the same spot for many hours. After moving the
text window away from the affected area, after a few hours, the
burned-in image started to blur, and by the next day, it was gone.

Makes me wonder just how susceptible LCD panels are to image
burn-in, and why one portion of a panel would be more suspectible
than the rest of the same panel.