ZBrushCentral

Subtool disappeared

Hi,
I was sculpting my wall and after hitting ctrl+z (i hope i hit that) to just move step back, my subtool permanently disappeared…
It seems it is in scene, because i can zoom it but i cannot make it visible in any way… i tried to make it visible by ctrl+drag or shift+ctrl+click (just these masking abilities) but then program crash…
bug or i did something bad?