diff --git a/interface/wx/clipbrd.h b/interface/wx/clipbrd.h
index d1d337123a..c8fb6fc277 100644
--- a/interface/wx/clipbrd.h
+++ b/interface/wx/clipbrd.h
@@ -53,6 +53,13 @@
     }
     @endcode
 
+    @note On GTK, the clipboard behavior can vary depending on the configuration of
+          the end-user's machine. In order for the clipboard data to persist after
+          the window closes, a clipboard manager must be installed. Some clipboard
+          managers will automatically flush the clipboard after each new piece of
+          data is added, while others will not. The @Flush() function will force
+          the clipboard manager to flush the data.
+
     @library{wxcore}
     @category{dnd}
 
@@ -99,6 +106,10 @@ public:
         Currently this method is implemented in MSW and GTK and always returns @false
         otherwise.
 
+        @note On GTK, only the non-primary selection can be flushed. Calling this function
+              when the clipboard is using the primary selection will return @false and not
+              make any data available after the program exits.
+
         @return @false if the operation is unsuccessful for any reason.
     */
     virtual bool Flush();
diff --git a/samples/clipboard/clipboard.cpp b/samples/clipboard/clipboard.cpp
index 1b3e068183..9d608e43de 100644
--- a/samples/clipboard/clipboard.cpp
+++ b/samples/clipboard/clipboard.cpp
@@ -151,7 +151,8 @@ void MyFrame::OnFlush(wxCommandEvent &WXUNUSED(event))
         return;
     }
 
-    if ( !wxTheClipboard->AddData(new wxTextDataObject("Text from wx clipboard sample")) )
+    wxString clipData = wxString::Format("Text from wx clipboard sample at %s" , wxDateTime::Now().Format());
+    if ( !wxTheClipboard->AddData(new wxTextDataObject(clipData)) )
     {
         m_textctrl->AppendText("Failed to put text on clipboard.\n");
         return;
diff --git a/src/gtk/clipbrd.cpp b/src/gtk/clipbrd.cpp
index 6d6aad79f6..0c0b447d78 100644
--- a/src/gtk/clipbrd.cpp
+++ b/src/gtk/clipbrd.cpp
@@ -306,6 +306,8 @@ selection_handler( GtkWidget *WXUNUSED(widget),
     if ( !size )
         return;
 
+    wxLogTrace(TRACE_CLIPBOARD, "Valid clipboard data found");
+
     wxCharBuffer buf(size - 1); // it adds 1 internally (for NUL)
 
     // text data must be returned in UTF8 if format is wxDF_UNICODETEXT
@@ -595,8 +597,19 @@ void wxClipboard::Clear()
 
 bool wxClipboard::Flush()
 {
-    gtk_clipboard_store( gtk_clipboard_get( GTKGetClipboardAtom() ) );
-    return true;
+    // Only store the non-primary clipboard when flushing. The primary clipboard is a scratch-space
+    // formed using the currently selected text.
+    if ( !m_usePrimary )
+    {
+        GtkClipboard* clipboard = gtk_clipboard_get(GDK_SELECTION_CLIPBOARD);
+
+        gtk_clipboard_set_can_store(clipboard, NULL, 0);
+        gtk_clipboard_store(clipboard);
+
+        return true;
+    }
+
+    return false;
 }
 
 bool wxClipboard::Open()