sigui: only enable Verify and Install when there are signatures.

win32/clamav-for-windows/sigui/SigUI/GUIFrame.cpp

@@ -264,6 +264,7 @@ GUIFrame::GUIFrame( wxWindow* parent, wxWindowID id, const wxString& title, cons
 	bSizer7->Add( sbSizer4, 1, wxALL|wxEXPAND, 5 );
 	
 	m_install = new wxButton( m_panel_sigman, wxID_ANY, _("Verify and &Install signatures"), wxDefaultPosition, wxDefaultSize, 0 );
+	m_install->Enable( false );
 	m_install->SetToolTip( _("Check that the signature files are well formed and install them in ClamAV's database directory") );
 	
 	bSizer7->Add( m_install, 0, wxALL|wxALIGN_CENTER_HORIZONTAL, 5 );

win32/clamav-for-windows/sigui/SigUI/SigUIMain.cpp

@@ -754,6 +754,7 @@ void SigUIFrame::m_local_addOnButtonClick( wxCommandEvent& WXUNUSED(event) )
 	    m_sig_candidates->Append(path);
 	}
 	m_local_remove->Enable(!m_sig_candidates->IsEmpty());
+	m_install->Enable(!m_sig_candidates->IsEmpty());
     }
 }
 
@@ -766,6 +767,7 @@ void SigUIFrame::m_local_removeOnButtonClick( wxCommandEvent& WXUNUSED(event) )
         m_sig_candidates->Delete(selections[--n]);
     }
     m_local_remove->Enable(!m_sig_candidates->IsEmpty());
+    m_install->Enable(!m_sig_candidates->IsEmpty());
 }
 
 void SigUIFrame::OnTerminateInstall(wxProcessEvent &event)

win32/clamav-for-windows/sigui/SigUI/WxWizFrame.fbp

@@ -1834,7 +1834,7 @@
                                             <property name="context_help"></property>
                                             <property name="context_menu">1</property>
                                             <property name="default">0</property>
-                                            <property name="enabled">1</property>
+                                            <property name="enabled">0</property>
                                             <property name="fg"></property>
                                             <property name="font"></property>
                                             <property name="hidden">0</property>