Index: /trunk/src/VBox/Frontends/VirtualBox/src/guestctrl/UIFileManagerTable.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/guestctrl/UIFileManagerTable.cpp	(revision 78057)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/guestctrl/UIFileManagerTable.cpp	(revision 78058)
@@ -783,4 +783,8 @@
         m_pSearchLineEdit->hide();
         m_pSearchLineEdit->setClearButtonEnabled(true);
+        m_searchLineUnmarkColor = m_pSearchLineEdit->palette().color(QPalette::Base);
+        m_searchLineMarkColor = QColor(m_searchLineUnmarkColor.green(),
+                                       0.5 * m_searchLineUnmarkColor.green(),
+                                       0.5 * m_searchLineUnmarkColor.blue());
         connect(m_pSearchLineEdit, &QLineEdit::textChanged,
                 this, &UIFileManagerTable::sltSearchTextChanged);
@@ -1302,4 +1306,5 @@
                 if (m_pSearchLineEdit)
                 {
+                    markUnmarkSearchLineEdit(false);
                     m_pSearchLineEdit->clear();
                     m_pSearchLineEdit->show();
@@ -1469,6 +1474,12 @@
 void UIFileManagerTable::performSelectionSearch(const QString &strSearchText)
 {
-    if (!m_pProxyModel | !m_pView || strSearchText.isEmpty())
-        return;
+    if (!m_pProxyModel | !m_pView)
+        return;
+
+    if (strSearchText.isEmpty())
+    {
+        markUnmarkSearchLineEdit(false);
+        return;
+    }
 
     int rowCount = m_pProxyModel->rowCount(m_pView->rootIndex());
@@ -1493,4 +1504,5 @@
         setSelection(index);
     }
+    markUnmarkSearchLineEdit(!pFoundItem);
 }
 
@@ -1532,3 +1544,16 @@
 }
 
+void UIFileManagerTable::markUnmarkSearchLineEdit(bool fMark)
+{
+    if (!m_pSearchLineEdit)
+        return;
+    QPalette palette = m_pSearchLineEdit->palette();
+
+    if (fMark)
+        palette.setColor(QPalette::Base, m_searchLineMarkColor);
+    else
+        palette.setColor(QPalette::Base, m_searchLineUnmarkColor);
+    m_pSearchLineEdit->setPalette(palette);
+}
+
 #include "UIFileManagerTable.moc"
Index: /trunk/src/VBox/Frontends/VirtualBox/src/guestctrl/UIFileManagerTable.h
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/guestctrl/UIFileManagerTable.h	(revision 78057)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/guestctrl/UIFileManagerTable.h	(revision 78058)
@@ -283,4 +283,7 @@
      *  if deletion can continue */
     bool            checkIfDeleteOK();
+    /** Marks/umarks the search line edit to signal that there are no matches for the current search.
+      * uses m_searchLineUnmarkColor and m_searchLineMarkColor. */
+    void            markUnmarkSearchLineEdit(bool fMark);
 
     UICustomFileSystemModel      *m_pModel;
@@ -290,4 +293,6 @@
     QGridLayout     *m_pMainLayout;
     QILineEdit      *m_pSearchLineEdit;
+    QColor           m_searchLineUnmarkColor;
+    QColor           m_searchLineMarkColor;
     QILabel         *m_pWarningLabel;