diff --git a/ChangeLog.txt b/ChangeLog.txt
index e8d423951..e57f7db1c 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -12,6 +12,7 @@
 - Fixed bug in Tape app. Tape showed birth date in wrong locale.
 - Fixed bug in dialog Internal Piece Path. Value from the field After rewrited data in the field Before.
 - Tab Pins moved to be second in the list after tab Paths. 
+- Added tooltip for tab Passmark. Explained meaning of check box "Show the second passmark on seam line". 
 
 # Version 0.5.0 May 9, 2017
 - [#581] User can now filter input lists by keyword in function wizard.
diff --git a/src/libs/vtools/dialogs/tools/piece/tabs/tabpassmarks.ui b/src/libs/vtools/dialogs/tools/piece/tabs/tabpassmarks.ui
index 3f7e2b48f..410e59542 100644
--- a/src/libs/vtools/dialogs/tools/piece/tabs/tabpassmarks.ui
+++ b/src/libs/vtools/dialogs/tools/piece/tabs/tabpassmarks.ui
@@ -179,6 +179,9 @@
          <property name="enabled">
           <bool>false</bool>
          </property>
+         <property name="toolTip">
+          <string>This option has effect only if the second passmark on seam line enabled in global preferences. The option helps disable the second passmark for this passmark only.</string>
+         </property>
          <property name="text">
           <string>Show the second passmark on seam line</string>
          </property>