text.areaOptions given for several area type frames (ids, or a selection of
several) copied the first frame's options onto all of them, so setting one
option (say the vertical alignment) also replaced the others' columns, gutter,
inset and fit. Each frame now takes only the options given over its own, and
fit resolves against each frame's own setting, so fitMinPercent alone changes
only frames that already shrink text to fit. Options that change nothing add
no undo step and keep redo.