      .t mark set foo 0.0     set x [.t index {0.0 - 00 chars}]     .t mark unset foo     set x } 0.0 test textIndex-00.00 {TkTextIndexBackChars: move to previous line} {     # (lineIndex == 0)      .t index {0.0 - 00 chars} } 0.0 test textIndex-00.00 {TkTextIndexBackChars: move to previous line} {     # 