This is a list of things to check when testing window size/pos functions.
===

gtk_widget_set_size_request():
 - causes the widget to request the given size
 - for toplevel windows, changes the default-requested size if 
   no default size is set and gtk_window_resize() has not been called
 - passing -1 for either width or height reverts to "natural" request
   in that dimension
 - passing 0 is allowed, and results in requisition of 1x1 
   (0x0 is a permitted requisition, but equivalent to 1x1, 
   we use 1x1 for implementation convenience)
 - causes notifies on width_request, height_request properties

gtk_window_resize():
 - causes a configure request in all cases if the window is mapped, 
   unless the new size is the same as the old size
 - overrides the default size on map if the window is unmapped
 - allows size of 0, equivalent to 1
 - clamped to geometry hints

gtk_window_set_default_size():
 - has no effect after the window has been mapped the first time, 
   unless the window has been unrealized in which case it should 
   have an effect
 - allows size of 0, equivalent to 1
 - allows size of -1 to unset the default size
 - clamped to geometry hints
 - gtk_window_resize() overrides it
 - causes notifies on default_width, default_height properties

gtk_window_get_default_size():
 - returns the values last passed to set_default_size(), including 
   -1. If set_default_size() has not been called, returns -1.

gtk_window_move():
 - always causes a configure request if the window is mapped, 
   unless the last configure request we sent was for the same
   position being moved to
 - position may be negative to move windows offscreen
 - if GTK_WIN_POS_CENTER_ALWAYS (or other future position 
   constraints we may add) is in effect, the move
   request is clamped to obey the constraints. thus
   calling gtk_window_move() on a CENTER_ALWAYS window 
   may trigger the window to bounce back to center if it 
   wasn't there
 - overrides all GTK_WIN_POS_ except CENTER_ALWAYS

gtk_window_get_size():
 - obtains the client-side known size of widget->window, 
   as last received from a configure event
 - prior to mapping, returns the default size we will request
 - between realization and mapping, computes default size 
   rather than looking at widget->window up-to-date size, 
   so the size will be correct after force-realizing a window

gtk_window_get_position():
 - obtains the point to be passed to gtk_window_move() in order
   to keep the window in its current position
 - round-trips to the server to get the position; this is suboptimal
   from both a race condition and speed standpoint but required to get
   window frame size
 - if the window is unmapped, returns the default position we will 
   request

gtk_window_set_position():
 - not the inverse of get_position(), sadly
 - modifies the default positioning of the window
 - if set to CENTER_ALWAYS and the window is mapped, results in a
   configure request moving the window to the center, unless the 
   window was already centered
 - ignored if gtk_window_move() called, with the exception 
   of CENTER_ALWAYS

gtk_window_parse_geometry():
 - parses a standard X geometry string
 - toggles on one or both of GDK_HINT_USER_SIZE, GDK_HINT_USER_POS
 - "xprop" shows user size/position are set on the window
 - calls gtk_window_set_default_size() to set the window size
 - calls gtk_window_move() to set the window position
 - calls gtk_window_set_gravity() to set the window gravity

gtk_window_reshow_with_initial_size():
 - for use by GUI builders; unrealizes and re-shows the window, 
   using default size (and also position, but position 
   is reset on any hide anyway)
 - window should be positioned and sized as it was on initial map,
   barring odd window managers

gtk_window_set_geometry_hints():
 - if a hint is set with this function, we do not override it
   in other parts of the code

General behavior
===

 - no infinite loops or nasty fighting-the-user flicker during 
   operations such as moving/resizing a window

Properties
===

GtkWindow::default_width, GtkWindow::default_height:
 - default_width is -1 if unset, or >= 0 if 
   a default width is set
 - default_height is -1 if unset, or >= 0 if
   a default height is set

GtkWindow::allow_grow, GtkWindow::resizable:
 - equivalent properties; changing one notifies on the other
 - if FALSE, we set the min size to the max size in the geometry 
   hints. 
 - If the app programmer has called gtk_window_set_geometry_hints()
   however and set min or max size, we don't replace the hint they
   set.

GtkWidget::width_request, GtkWidget::height_request:
 - if -1, default requisition of widget is used
 - otherwise, override default requisition