Web Forms Designer crashes with specific combination of CSS rules in Visual Studio 2013

Symptoms

When you use Web Forms Designer to edit a Web Form in Visual Studio 2013, Visual Studio crashes. This issue occurs when the page uses a specific combination of Cascading Style Sheets (CSS) rules. For example, the page uses the folowing rules:

<style type="text/css">
  .class1 {
     line-height: 25px;
  }

  .class2 {
    font-size: 15px;
  }

  .class3 {
    line-height: inherit;
  }
</style>

If all these rules are applied to the same element in the HTML of the Web Form, Visual Studio crashes when the file is opened in Web Form Designer.

Cause

Web Forms Designer may crash when you try to determine the correct font size if the line height is explicitly defined by one rule and then undefined by a different CSS rule.

Resolution

This update is available from the Microsoft Download Center.

Microsoft Download Center

The following file is available for download from the Microsoft Download Center:

Download Download the update package now.
For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

Prerequisites

This hotfix requires Visual Studio 2013 Update 5.

Restart information

You may have to restart the computer after you apply this hotfix.

Replacement information

This hotfix does not replace any previously released hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

File name	File version	File size	Date	Time	Platform
VS12-KB3124249.exe	12.0.40633.0	8,098,920	16-Dec-2015	0:56	x86

Workaround

To work around this issue, use one of the following methods if the CSS file can be changed:

Remove the line-height value for an element that has other styles defined.
Remove the font-size value for an element that has line height defined.