commit 50649f85c26dea55bc12ac559fc97619aed5d807
Author: Olivier Fourdan <ofourdan@redhat.com>
Date:   Wed Apr 11 11:09:00 2012 +0200

    wacom: Make the "Calibrate" button insensitive if there no match
    found for the screen tablet (calibration will fail anyway in this
    case)

diff --git a/panels/wacom/cc-wacom-page.c b/panels/wacom/cc-wacom-page.c
index 3a3128a..d381977 100644
--- a/panels/wacom/cc-wacom-page.c
+++ b/panels/wacom/cc-wacom-page.c
@@ -1054,6 +1054,10 @@ update_tablet_ui (CcWacomPage *page,
 		gtk_widget_destroy (WID ("display-mapping-button"));
 
 		gtk_widget_show (WID ("button-calibrate"));
+		if (gsd_wacom_device_get_display_monitor (page->priv->stylus) < 0)
+			gtk_widget_set_sensitive (WID ("button-calibrate"), FALSE);
+		else
+			gtk_widget_set_sensitive (WID ("button-calibrate"), TRUE);
 		gtk_widget_show (WID ("display-link"));
 
 		gtk_container_child_set (CWID ("main-grid"),
