diff --git a/src/frontends/qt4/ui/PrefDocHandlingUi.ui b/src/frontends/qt4/ui/PrefDocHandlingUi.ui
index 949e2b6adf..dbded3384b 100644
--- a/src/frontends/qt4/ui/PrefDocHandlingUi.ui
+++ b/src/frontends/qt4/ui/PrefDocHandlingUi.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>403</width>
-    <height>416</height>
+    <width>413</width>
+    <height>497</height>
    </rect>
   </property>
   <property name="sizePolicy">
@@ -141,8 +141,12 @@
       </item>
       <item row="2" column="0">
        <widget class="QCheckBox" name="saveCompressedCB">
+        <property name="toolTip">
+         <string>If this is checked, new documents will be saved in a compressed binary-format by default.
+Existing documents will still be saved in their current state (compressed or uncompressed).</string>
+        </property>
         <property name="text">
-         <string>&amp;Save documents compressed by default</string>
+         <string>&amp;Save new documents compressed by default</string>
         </property>
        </widget>
       </item>
@@ -168,7 +172,8 @@
       <item row="1" column="0">
        <widget class="QCheckBox" name="singleInstanceCB">
         <property name="toolTip">
-         <string>Whether to open documents in an already running instance of LyX.&#x0a;(Set the LyXServer pipe path and restart LyX to enable this feature)</string>
+         <string>Whether to open documents in an already running instance of LyX.
+(Set the LyXServer pipe path and restart LyX to enable this feature)</string>
         </property>
         <property name="text">
          <string>Use s&amp;ingle instance</string>