Shrink rowdata after ECH
Really minor leftover from #136 (closed):
echo -e '\e[70X'
Then narrow the window to <70 columns, notice that this line gets wrapped into two. That is, the rowdata contanis 70 erased characters (U+0000 as we denote them) after an ECH 70.
ECH could detect if the end of a line is being erased using the default attributes, and shrink rowdata in that case. Perhaps other escape sequences are affected too, I'm not sure.