Even with a U2 that has only two brief Frames, I get the problem--if I
switch back and forth among screen widths!
My normal SW is 120. If I do:
SW=80
SW=120
I get the problem.
It's not the numbers, it's something about switching screen widths (or
about memory). Sometimes I can get out the problem by changing to some
other SW and then changing back to 120.
Changing SL doesn't affect it.
Re-loading XYWWWEB.U2 doesn't affect it. Re-loading SETTINGS.DFL (which has
sw=120 in it) doesn't affect it.
Re-booting doesn't affect it.
'Tis a puzzlement.