I swear I used to understand this stuff. I plead old age. Why do I get
two different results from the float placements here:

definefloat[mysidebar][mysidebars]
setupfloat[mysidebar][leftmargindistance=-.25in,rightmargindistance=-.25in,outer,none]

defineframedtext [sidebartext]
[width=.4textwidth,bodyfont=small,corner=round,background=color,backgroundcolor=lightgray,align=flushleft]

starttext
This is a bit of text
placefloat[sidebar][leftmargindistance=-.25in,rightmargindistance=-.25in,outer,none]{}{
startsidebartext
This is a short sidebar
stopsidebartext
}
And something to follow.

A bit of text
placemysidebar{}{
startsidebartext
This is a short sidebar
stopsidebartext
}
And something to follow.

stoptext