Alt+Q reflow does not take into account indentation

[SuzanneSoy]

Racket version: 20160914-62f5b2c (today's nightly)

With the default paragraph width of 60, the X on the third line is character number 61, but Alt+Q does nothing. If an extra character is added, then Alt+Q correctly moves the last word of the third line to the fourth.

#lang scribble/manual
1234@tt{9 123456789 123456789 123456789 123456789 1234567890
 23456789 123456789 123456789 123456789 123456789 1234567890X
 23456789}

If an extra level of indentation is added, then two characters past the limit are ignored, so I think the spaces due to indentation are ignored.

#lang scribble/manual
1234@tt{9 123456789 123456789 123456789 123456789 123456789 123456789 1234567890
 @emph{89 123456789 123456789 123456789 123456789 123456789 123456789 1234567890
  3456789 123456789 123456789 123456789 123456789 123456789 123456789 1234567890XY
  3456789}}