Sometimes tty left part of the screen blank after covering the entire
screen with a menu and then switching to a smaller menu that should
have redrawn the map as background. To reproduce:
| O - puts up a big menu
| : - enter a search string: "autopickup exception"
| <return> - dismiss the menu after the search makes one match
The autopickup exceptions sub-menu will be shown, with a small border
of map around it but most of the screen blank. (This behavior was
present before 3.6.0 but may not have been noticed because when the
discovered map doesn't extend to the corner menu's area, the blank
map probably seemed to be intentional. But if a fringe of map gets
drawn around the menu, that clearly isn't intended.) The incomplete
map is temporary; once menu is dismissed, it gets redrawn properly.
This adds a flush_screen() call after one particular docrt() call.
Perhaps docrt() should end with its own flush_screen() instead, but
that would require a lot more testing.
Closes#673
87f08dbeba