diff --git a/pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotFileGenerator.java b/pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotFileGenerator.java
index 56b16c1..0e8f5b1 100644
--- a/pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotFileGenerator.java
+++ b/pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotFileGenerator.java
@@ -53,12 +53,11 @@ public class GnuplotFileGenerator {
 		appendfln(result, "set output \"%s\"", settings.getOutput().toAbsolutePath().toString().replace("\\", "/"));
 
 		// marker lines that show which area will be zoomed
-		final long minDate = Long.parseLong(settings.getxAxisSettings().getFrom());
-		final long maxDate = Long.parseLong(settings.getxAxisSettings().getTo());
-		appendfln(result, "set arrow from " + (minDate + (maxDate - minDate) * 0.25) + "," + graphOffset
-				+ " rto graph 0,1 lt 3 lc rgb \"#EEEEEE\" nohead");
-		appendfln(result, "set arrow from " + (minDate + (maxDate - minDate) * 0.75) + "," + graphOffset
-				+ " rto graph 0,1 lc rgb \"#EEEEEE\" nohead");
+		appendfln(result, "set arrow from graph 0.25,0 rto graph 0,1 lc rgb \"#EEEEEE\" nohead");
+		appendfln(result, "set arrow from graph 0.75,0 rto graph 0,1 lc rgb \"#EEEEEE\" nohead");
+
+		// marker line for the 60 second threshold
+		appendfln(result, "set arrow from graph 0, first 60000 rto graph 1,0 lc rgb \"#EEEEEE\" nohead");
 
 		if (settings.isKeyOutside()) {
 			appendfln(result, "set key outside");