Many things are missing in the current library.
The ones with a "*" are priorities.

WIDGETS:
	- Alignement left/right in an horizontal widget
	- Text formatting
	- Semantic Lens
	- Focus navigation with keyboard
	- Framing (border + name) : decorator enhancement

LIBRARY CORE:
	* Use only one GC instead of 6 (start of OpenGL conversion)
	- Make a pile by attribute with a bit vector to indicate
	  which attributes where pushed (as it is yet done with GC's)
	  So in the most current case, there only one 'int' to push
	  to push all the attributes.
	  Define the attributes in current state dynamicly
	- zMw->size[0].alignement zMw->size[0].required for X axis ...
	  and [1] for Y axis.
	- Use OpenGL
	- zmw_name must not be called with the same name for sibling.
	- Create an zmw_action_assert to verify widget tree ?
	- Having children "not_used_to_compute_parent_size" in CHILDREN
	  complexify the size computation.
	  Should the CHILDREN_VISIBLE table be created ?
	- Add a zmw_modified() to zmw_activated() for text or scrollbar
	  modification.
	- Should zmw_action_dispatch_event be separated into
	  zmw_dispatch_button_press, zwm_dispatch_key_press, ...
	  It will simplify the drag and drop operation,
	  zmw_dispatch_test_receptor, zmw_dispatch_drop, ...
	- Cursor shape change
	- Does the tips should appear if the mouse button is pressed?
	- Create zmw_font_name zmw_font_size zmw_font_weight ...
BUGS:
	* X window is locked (grab?) when debugging info is printed
	- Key pressed have not the current coordinates, but the last
	  one received.
	- A detached menu is invisible if its father is not visible
	  (can be corrected without problems)
	- A window in an invisible notebook page is not visible
	- In many widget, cursor draging must not go outside window
	  (scrollbar, table, ...) (it is due to bad x,y conversion because
	  the cursor change of window.)
	- filechooser at top level does not always appear in a framed window
	- image_from_file are not freed : when is the question.
	  Add a timestamp in resource in order to free images not
	  used for 1 minute ?
	  
NOT TO DO THINGS :
	- Test "nb_draw" instead of wait a small time in the tests.
	  This value is unpredictable (because there is event
	  and a timer, the two things are not synchronized...)

	- Create a shortcut to stop tree traversal (complex).
	  Very bad idea, some functions may need a full traversal.
	  It does not speed hugely things so it is not interesting.
