diff --git a/src/ui/qgscategorizedsymbolrendererv2widget.ui b/src/ui/qgscategorizedsymbolrendererv2widget.ui
index ddedf70876a..393649beeed 100644
--- a/src/ui/qgscategorizedsymbolrendererv2widget.ui
+++ b/src/ui/qgscategorizedsymbolrendererv2widget.ui
@@ -11,7 +11,16 @@
    </rect>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
-   <property name="margin">
+   <property name="leftMargin">
+    <number>0</number>
+   </property>
+   <property name="topMargin">
+    <number>0</number>
+   </property>
+   <property name="rightMargin">
+    <number>0</number>
+   </property>
+   <property name="bottomMargin">
     <number>0</number>
    </property>
    <item>
@@ -24,7 +33,14 @@
       </widget>
      </item>
      <item>
-      <widget class="QgsFieldExpressionWidget" name="mExpressionWidget" native="true"/>
+      <widget class="QgsFieldExpressionWidget" name="mExpressionWidget" native="true">
+       <property name="maximumSize">
+        <size>
+         <width>500</width>
+         <height>16777215</height>
+        </size>
+       </property>
+      </widget>
      </item>
      <item>
       <spacer name="horizontalSpacer">
diff --git a/src/ui/qgsgraduatedsymbolrendererv2widget.ui b/src/ui/qgsgraduatedsymbolrendererv2widget.ui
index 5cb88b970a6..dd384b5ebb9 100644
--- a/src/ui/qgsgraduatedsymbolrendererv2widget.ui
+++ b/src/ui/qgsgraduatedsymbolrendererv2widget.ui
@@ -11,7 +11,16 @@
    </rect>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
-   <property name="margin">
+   <property name="leftMargin">
+    <number>0</number>
+   </property>
+   <property name="topMargin">
+    <number>0</number>
+   </property>
+   <property name="rightMargin">
+    <number>0</number>
+   </property>
+   <property name="bottomMargin">
     <number>0</number>
    </property>
    <item>
@@ -150,7 +159,14 @@
         <number>0</number>
        </property>
        <item>
-        <widget class="QgsFieldExpressionWidget" name="mExpressionWidget" native="true"/>
+        <widget class="QgsFieldExpressionWidget" name="mExpressionWidget" native="true">
+         <property name="maximumSize">
+          <size>
+           <width>500</width>
+           <height>16777215</height>
+          </size>
+         </property>
+        </widget>
        </item>
        <item>
         <spacer name="horizontalSpacer">