diff --git a/src/calibre/ebooks/conversion/plumber.py b/src/calibre/ebooks/conversion/plumber.py
index df1098da8f..3a18b40539 100644
--- a/src/calibre/ebooks/conversion/plumber.py
+++ b/src/calibre/ebooks/conversion/plumber.py
@@ -369,9 +369,8 @@ OptionRecommendation(name='remove_paragraph_spacing_indent_size',
         help=_('When calibre removes blank lines between paragraphs, it automatically '
             'sets a paragraph indent, to ensure that paragraphs can be easily '
             'distinguished. This option controls the width of that indent (in em). '
-            'If you set this value to 0, then the indent specified in the input '
-            'document is used, unless you also set the insert line between '
-            'paragraphs option.')
+            'If you set this value negative, then the indent specified in the input '
+            'document is used, that is, calibre does not change the indentation.')
         ),
 
 OptionRecommendation(name='prefer_metadata_cover',
diff --git a/src/calibre/ebooks/oeb/transforms/flatcss.py b/src/calibre/ebooks/oeb/transforms/flatcss.py
index 6458ca80b0..474bb0eb32 100644
--- a/src/calibre/ebooks/oeb/transforms/flatcss.py
+++ b/src/calibre/ebooks/oeb/transforms/flatcss.py
@@ -321,7 +321,7 @@ class CSSFlattener(object):
                 cssdict['margin-top'] = cssdict['margin-bottom'] = \
                     '%fem'%self.context.insert_blank_line_size
             indent_size = self.context.remove_paragraph_spacing_indent_size
-            keep_indents = indent_size == 0.0 and not self.context.insert_blank_line
+            keep_indents = indent_size < 0.0
             if (self.context.remove_paragraph_spacing and not keep_indents and
                 cssdict.get('text-align', None) not in ('center', 'right')):
                 cssdict['text-indent'] =  "%1.1fem" % indent_size
diff --git a/src/calibre/gui2/convert/look_and_feel.ui b/src/calibre/gui2/convert/look_and_feel.ui
index 055d569212..2c63ce4846 100644
--- a/src/calibre/gui2/convert/look_and_feel.ui
+++ b/src/calibre/gui2/convert/look_and_feel.ui
@@ -84,7 +84,7 @@
         <string>...</string>
        </property>
        <property name="icon">
-        <iconset>
+        <iconset resource="../../../../resources/images.qrc">
          <normaloff>:/images/wizard.png</normaloff>:/images/wizard.png</iconset>
        </property>
        <property name="iconSize">
@@ -225,12 +225,21 @@
      <property name="toolTip">
       <string>&lt;p&gt;When calibre removes inter paragraph spacing, it automatically sets a paragraph indent, to ensure that paragraphs can be easily distinguished. This option controls the width of that indent.</string>
      </property>
+     <property name="specialValueText">
+      <string>No change</string>
+     </property>
      <property name="suffix">
       <string> em</string>
      </property>
      <property name="decimals">
       <number>1</number>
      </property>
+     <property name="minimum">
+      <double>-0.100000000000000</double>
+     </property>
+     <property name="singleStep">
+      <double>0.100000000000000</double>
+     </property>
     </widget>
    </item>
    <item row="6" column="3">