M src/FbTk/App.cc → src/FbTk/App.cc

@@ -60,8 +60,13 @@ // a blank string, rather than a null string, so we make them equivalent
     if (displayname != 0 && displayname[0] == '\0')
         displayname = 0;
     m_display = XOpenDisplay(displayname);
-    if (!m_display)
-        throw std::string("Couldn't connect to XServer");
+    if (!m_display) {
+        if (displayname) {
+            throw std::string("Couldn't connect to XServer") + displayname;
+        } else {
+            throw std::string("Couldn't connect to XServer passing null display");
+        }
+    }
 
     FbStringUtil::init();
 }