Now I see …
It said so in the manual all along (Tools chapter), but the XYZ axes under Tool: Modifiers: Deformation are those of the object preview window, NOT the axes of the Transform gimbals
So when you rotate a 3d tool in the object preview window you are changing where the XYZ poles fall on the tool (for the purpose of deformation)
Just thought I would highlight that for the newcomers since it took me so long to get it 
:rolleyes:
you can also drag the red cursor in the preview window to change where the pivot point is. This can also be constrained by the shift key.
I also had the same revelation as you Havran, amongst many other Doh!, Aha, Cool and What the!? moments
This link might be interesting to newcomers, WANTED: Most Valuable Learning Tips
Hi
You should be read all the posts
This one particulary :rolleyes:
Red Cursor was in light
Have happy Zbrushing 
Pilou
something else about the Object Preview Window (under Tool: Modifiers) is that there are two little buttons in the upper corners – same controls as in the Brush Preview in the Draw palette
upper left button toggles (turns on/off) the spinning preview mode – direction and speed are set by dragging the mouse over the preview when this mode is active
upper right button toggles the visibility of the reference plane in the preview
this I learned because my preview started spinning and I had no idea why
it’s in the manual, but kind of indirectly – mentioned in the Tools chapter and fully described in the Draw-palette chapter