Fix visual glitches in search-bar

Closes https://github.com/lxqt/qterminal/issues/249

lib/SearchBar.cpp

@@ -26,6 +26,7 @@
 SearchBar::SearchBar(QWidget *parent) : QWidget(parent)
 {
     widget.setupUi(this);
+    setAutoFillBackground(true); // make it always opaque, especially inside translucent windows
     connect(widget.closeButton, SIGNAL(clicked()), this, SLOT(hide()));
     connect(widget.searchTextEdit, SIGNAL(textChanged(QString)), this, SIGNAL(searchCriteriaChanged()));
     connect(widget.findPreviousButton, SIGNAL(clicked()), this, SIGNAL(findPrevious()));

lib/SearchBar.ui

@@ -66,16 +66,11 @@
       <string>...</string>
      </property>
      <property name="icon">
-      <iconset>
-       <normaloff/>
-      </iconset>
+      <iconset theme="preferences-system"/>
      </property>
      <property name="popupMode">
       <enum>QToolButton::InstantPopup</enum>
      </property>
-     <property name="arrowType">
-      <enum>Qt::DownArrow</enum>
-     </property>
     </widget>
    </item>
   </layout>