ZBrushCentral

can't scale on xy plane...

Hi ,guys, I 'm kinda new to this, but with Zbrush 2018, I can no longer scale my subtool on any plane axis( xy, xz, …) by holding down the ALT button and drag the scale cube. I don’t know if this issue is happening to anyone of you, a little help, plz. Thx.

I have same problem on win7.