I tried the same test with software renderer and r300 accelerated renderer. With
blender-2.41 in native linux code and blender-2.42-rc2 for windows using wine
emulation (works fine too but with the same bug).

The bug is mostly on vertex selection. It occurs on blender only when back
culling is activated (little cube button titled "limit selection to visible
(clipped with depth buffer)"), and only in solid, shaded or textured display
(not in wireframe).

On this screen capture :
http://popolon.free.fr/Selection_bug.png

I selected the vertices with b key (rectangle selection)

* Up picture is the buggy selection in solid mode. only some vertices are
selected more or less randomly.
* Bottom picture is the good behavior in wireframe mode (all vertices are selected).

Face or edge selection works fine in every cases.

There is also a bug with lasso selection, the lasso is drawn on the screen
without selecting vertice, and the stroke don't disappear after move up mouse
button. I believe blender have to catch an event from Mesa/r300 driver that
doesn't come ???



I reported it on bug #6085 first (but with less informations), that was a bug
about blender crash, but this bug is closed as blender doesn't crash anymore.