What to do when Visual Studio keeps opening your webtests in the wrong type of editor

Is Visual Studio opening your .webtest files in the XML editor instead of the GUI? You can fix this by editing the .csproj file of the project that contains the .webtests.

Find the line for your webtest and remove the following line below it:

<SubType>Designer</SubType>

Restart Visual Studio and the next time you double click on the test, it will be opened in the GUI editor.