diff -r 82bfc75bcd9d -r 105c20fdeb19 dialogs/DurationEditorDialog.py
--- a/dialogs/DurationEditorDialog.py	Fri Oct 05 13:48:54 2018 +0300
+++ b/dialogs/DurationEditorDialog.py	Fri Oct 05 14:22:01 2018 +0300
@@ -25,6 +25,7 @@
 
 
 from __future__ import absolute_import
+from __future__ import division
 import re
 
 import wx
@@ -139,10 +140,10 @@
 
         not_null = False
         duration = "T#"
-        for value, format in [((int(milliseconds) / DAY),             "%dd"),
-                              ((int(milliseconds) % DAY) / HOUR,      "%dh"),
-                              ((int(milliseconds) % HOUR) / MINUTE,   "%dm"),
-                              ((int(milliseconds) % MINUTE) / SECOND, "%ds")]:
+        for value, format in [((int(milliseconds) // DAY),             "%dd"),
+                              ((int(milliseconds) % DAY) // HOUR,      "%dh"),
+                              ((int(milliseconds) % HOUR) // MINUTE,   "%dm"),
+                              ((int(milliseconds) % MINUTE) // SECOND, "%ds")]:
 
             if value > 0 or not_null:
                 duration += format % value