Tabs in text editor

In Windows hitting tab converts to four spaces, but in Wine it becomes 16!

How do I change the number of spaces inserted?

For info:
MUSHclient 4.91
Windows 7
Unbuntu 13.10
Wine 1.4.1 (MUSHclient running under XP)

I don't know it does that, because the editor control should work the same. All I can suggest is use spaces instead, or an external editor and copy and paste stuff back where you want it.

Okay, I'll convert tabs to spaces. I do love my tabs though.