_getCairoSurfaceFromContext() issue/doubt

Guys!

Firstly, so sorry! I'm a bit absent from community last weeks.

Today, a holiday here, I've been trying to understand bizar bug with
Caret on OS X.
So, I cloned Andrei's branch and put 2 debug messages on
gr_CairoGraphics.cpp. One in line 1393 (before
cairo_surface_create_similar()'s call) and another in line 1399
(immediately after cairo_surface_create_similar();s call).

The result was:

DEBUG: FIDENCIO before cairo_surface_create_similiar:
width: 1606411120
height: 0
x:5.000000
y:15.000000
DEBUG: FIDENCIO: after cairo_surface_create_similar:
width: 0
height: -1
x:5.000000
y:15.000000

Looking for it using GDB I saw that pointer's address is not being changed. :-\

Could someone gimme some tip/trick about what is happening or just
tell me "it's the expected behavior"?

Best Regards,

-- 
Fabiano Fidêncio