Using as an example of starting the April 30 version 4.1.7.0429 version AjaxControlToolkitSampleSite.zip shifting the focus on the textbox the page is not erased the mask, the result is visible in the attached figure.
Comments: The fix for this problem will be included into version 15.1.2 of ASP.NET AJAX Control Toolkit.
Comments: The fix for this problem will be included into version 15.1.2 of ASP.NET AJAX Control Toolkit.