set margins in code instead of .ui file

Author: alexbruy

src/gui/symbology-ng/qgssymbolselectordialog.cpp

@@ -230,6 +230,7 @@ QgsSymbolSelectorWidget::QgsSymbolSelectorWidget( QgsSymbol* symbol, QgsStyle* s
   mPresentWidget = nullptr;
 
   setupUi( this );
+  this->layout()->setContentsMargins( 0, 0, 0, 0 );
 
   // setup icons
   btnAddLayer->setIcon( QIcon( QgsApplication::iconPath( "symbologyAdd.svg" ) ) );

src/ui/qgssymbolselectordialogbase.ui

@@ -14,18 +14,6 @@
    <string>Form</string>
   </property>
   <layout class="QGridLayout" name="gridLayout_2">
-   <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>9</number>
-   </property>
    <item row="1" column="0">
     <layout class="QHBoxLayout" name="pushBtnBox">
      <property name="spacing">
@@ -148,7 +136,16 @@
       <property name="spacing">
        <number>0</number>
       </property>
-      <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>