Particles are not visible with ParticlePanel and SpriteParticleRenderer

When SpriteParticleRender has been chosen as renderer for particle system and texture added, particles become invisible in ParticlePanel.

Steps to reproduce:
1) Run "python Tut-Particle-Panel.py" from Particles sample program.
2) Open dust.ptf, it will render dust, but...
3) Save it under a different name in the same folder
4) Open it up and see nothing

Changing texture file does not change the outcome.

OS: ubuntu 64bit
Version: 1.7.0