All

x garbage collection in lsm_property_manager
- CSS support
x gtk-doc support
x single <lsm.h> include
- multithread safety
- registered elements (by id) are never unregistered !!! (see lsm_dom_document_register_element). Also, the id hash table is not
  necessary.

Mathml

- merge space and space list attribute.
- may be merge space and lentgh attribute (for example by extending GMATHML_UNIT with the different GMATHML_NAMED_SPACE).
- check memory allocation in gmathmlattributes.
- also check array access in update/measure/layout/render methods.
- need_layout flag (extend attribute to mark them as layout invalidator (FALSE for color attribute, for example)).
- stretching support (done for under/over).
- mtr/mtd attribute support.
- get_embellished_core for mmultiscripts, semantics, maction, mrow (and infered rows) (Mathml 2.0 3.2.5.7.3)
- is_inferred_row for merror, mpadded, menclose,
- build a view tree for data specific to a given view.
- handle correctly PT and PX units.
- handle table alignment. Correctly compute axis position in a row.
- merge attribute code in presentation_token and style_element.
- maxsize and minsize support for mo

SVG

x check for recursions
x don't use cairo_stroke for simple text, but pango_cairo_show_layout instead.
- take group opacity into account when stroking or filling with pattern (like what was done for gradient)
- really implement get_extents for all elements
- don't ignore an element with visibility != visible when clipping
- don't include extents of an element with display == none
x don't use push_group when filling or stroking shapes with group opacity < 1.0

x add support of subregion for filter primitives
x group opacity should happen after filter
x add support for filter BackgroundImage and BackgroundAlpha 
- handle width and height of enable-background=new
x fix SourceAlpha

- feComposite: add support for arithmetic
- feSpecularLighting: implementation needed
- feTurbulence: TODO
- switch: handle requiredFeatures, requiredExtensions and systemLanguage
- text, tspan: correct implementation needed

And many many more things to do...
