fltk backend in 3.8.0 on ubunto 13.10

[c.]

Hi,

I just compiled Octave 3.8.0 on Ubuntu 13.10 and I noticed
some strange behaviour when plotting with the FLTK backend.

When the figure window opens it goes to the forefront an takes the focus;
if I click on a different window, the window decorations move to the 
background but the figure remains in the foreground.

The above happens both with octave-cli and octave-gui, but in the latter
case I cannot bring back focus to the command prompt and I see these error 
messages:


>> plot (randn (3))
OpenGL Warning: glFlushVertexArrayRangeNV not found in mesa table
OpenGL Warning: glVertexArrayRangeNV not found in mesa table
OpenGL Warning: glCombinerInputNV not found in mesa table
OpenGL Warning: glCombinerOutputNV not found in mesa table
OpenGL Warning: glCombinerParameterfNV not found in mesa table
OpenGL Warning: glCombinerParameterfvNV not found in mesa table
OpenGL Warning: glCombinerParameteriNV not found in mesa table
OpenGL Warning: glCombinerParameterivNV not found in mesa table
OpenGL Warning: glFinalCombinerInputNV not found in mesa table
OpenGL Warning: glGetCombinerInputParameterfvNV not found in mesa table
OpenGL Warning: glGetCombinerInputParameterivNV not found in mesa table
OpenGL Warning: glGetCombinerOutputParameterfvNV not found in mesa table
OpenGL Warning: glGetCombinerOutputParameterivNV not found in mesa table
OpenGL Warning: glGetFinalCombinerInputParameterfvNV not found in mesa table
OpenGL Warning: glGetFinalCombinerInputParameterivNV not found in mesa table
OpenGL Warning: glDeleteFencesNV not found in mesa table
OpenGL Warning: glFinishFenceNV not found in mesa table
OpenGL Warning: glGenFencesNV not found in mesa table
OpenGL Warning: glGetFenceivNV not found in mesa table
OpenGL Warning: glIsFenceNV not found in mesa table
OpenGL Warning: glSetFenceNV not found in mesa table
OpenGL Warning: glTestFenceNV not found in mesa table
OpenGL Warning: No pincher, please call crStateSetCurrentPointers() in your SPU

Has anyone else experienced this behaviour? 
Should I submit a bug?

c.