@@ -2605,8 +2605,8 @@ setMethod("drawGD", signature("AlignmentsTrack"), function(GdObject, minBase, ma

     tck <- tckText

     exponent <- if (is.null(.dpOrDefault(GdObject, "exponent"))) {

         exp <- 0

-        while (all(tck[tck > 0] / 10^exp >= 1)) {

-            exp <- exp + 3

+        while (all(abs(tck)[abs(tck) > 0] / 10^exp >= 1)) {

+          exp <- exp + 3

         }

         exp - 3

     } else {