Version:           2.4-snapshots (using KDE 4.5.5) 
OS:                Linux

The following was noted in Krita Alpha-2 (downloaded and compiled Jun 26, 2011).

When I edit the Size or Opacity Pressure curve in Pixel or Smudge Brush, save a preset and load it back, then the curve is reset to default. And these curves have no effect even before save / load. 

This occurs only when modifying a curve in the preset, which have not curve previously edited (i.e., have a default straight line). If the preset (from Krita Alpha-1) have previously edited curve, I can edit it, save, load and the curve is not disappears.

Also, when I turn on some other tablet modifier in Size property settings (Fuzzy for example), the Pressure curve begin to work, and can be saved/loaded. 

Reproducible: Always

Steps to Reproduce:
In Pixel brush engine settings window, add some points to Size Pressure curve, save a preset and load it. 

Actual Results:  
The curve reset to default straight line

Expected Results:  
Curves must normally save and load

OS: Linux (x86_64) release 2.6.35-30-generic (Ubuntu 10.10)
Compiler: cc