set cursor to start of textbox when focusing FS#2243

This works around a new "feature/bug" of Firefox 4.

lib/scripts/edit.js

@@ -300,7 +300,11 @@ addInitEvent(function (){
     if(edit_text) {
         if(edit_text.readOnly) return;
 
-        // set focus
+        // set focus and place cursor at the start
+        var sel = getSelection(edit_text);
+        sel.start = 0;
+        sel.end   = 0;
+        setSelection(sel);
         edit_text.focus();
     }