FLTK widgets do not redraw

Widgets in FLTK 1.3 applications are not redrawn in response to Fl_Widget::redraw() calls; one must force a redraw by moving or resizing the application window. This can be seen in Dillo-Win32 (http://dillo-win32.sourceforge.net/), for example, when a newly-loaded page is displayed as a blank box until the browser window is moved or resized; it also affects other things like the tabs widget in Dillo's Preferences dialog.

I am aware that FLTK widgets do not redraw automatically when updated; the application in question calls Fl_Widget::redraw() when necessary, and has been confirmed to work correctly on several Windows systems (including NT 4.0, 98 SE, and XP). I intend to test other FLTK applications when I get a chance, to confirm that this behavior is not specific to Dillo.