 <p>Try put this code in your page</p> <pre><code>&lt;script type="text/javascript"&gt; Sys.Application.add_load(function () { Sys.Extended.UI.MaskedEditBehavior.prototype._MoveDecimalPos = function () { var e = this.get_element(); var wrapper = Sys.Extended.UI.TextBoxWrapper.get_Wrapper(e); var curpos = this._LogicFirstPos; var max = this._LogicLastPos; var posDc = -1; while (curpos &lt; max) { if (wrapper.get_Value().substring(curpos, curpos + 1) == this.get_CultureDecimalPlaceholder()) { posDc = curpos + 1; break; } curpos++; } if (posDc == -1) { return; } this.setSelectionRange(posDc, posDc); }; }); &lt;/script&gt; </code></pre>