I have also noticed that there is some kind of "automatic tabbing" in case there are more actual TAB characters in the text line than is the number of the defined tab stops. This is fine, but I suggest it should be documented, as it affects the layout of the text also in case a part of it is too big to fit in the predefined tab stops. If one is not aware of this behaviour, the output might seem to be buggy at the first glance...
Yeah... there're tricks about that.
But you're right, if there're more tabs characters than defined by SetTabs the "automatic" tabs are used (Win32 and Gtk2).
Currently they behave differently on each widgetset, so this is a subject to change!
I.e. Win32 would use it's own "default" tab length (which is similar to Open Office Writer or MS Word)
Gtk2 would use the last tab length
Cocoa would just start a new line.
So beware!
I'll document the behavior as soon as it's works on all platforms the same (very likely to reflect what Win32 does).