IdeaList looks for a special code sequence at the end of a text defining the
tabulator width.

These codes are as follows:
If the last 4 bytes of a text are CR-Tab-CR-Tab and these are preceded by
a number of tabs, that defines the tab width.
For instance this text is coded to use a tab width of 5 as the last bytes
are Tab-Tab-Tab-Tab-Tab-CR-Tab-CR-Tab.

The evidence:
1234567890123456789012345678901
	6	1	6	1	6	1 (here with tabs of 5 before every digit)
     6    1    6    1    6    1 (here only with blanks)

Don't forget to reset the tab width to the old value afterwards.